Search

The detection of aromatic aldehydes, considered potential genotoxic impurities, holds significant importance during drug development and production. Current analytical methods necessitate complex pre-treatment processes and exhibit insufficient specificity and sensitivity. This study presents the utilization of naphthalenediimide as a pre-column derivatisation reagent to detect aromatic aldehyde impurities in pharmaceuticals via high-performance liquid chromatography (HPLC). We screened a series of derivatisation reagents through density functional theory (DFT) and investigated the phenomenon of photoinduced electron transfer (PET) for both the derivatisation reagents and the resulting products. Optimal experimental conditions for derivatisation were achieved at 40 °C for 60 min. This approach has been successfully applied to detect residual aromatic aldehyde genotoxic impurities in various pharmaceutical preparations, including 4-Nitrobenzaldehyde, 2-Nitrobenzaldehyde, 1,4-Benzodioxane-6-aldehyde, and 5-Hydroxymethylfurfural. The pre-column derivatisation method significantly enhanced detection sensitivity and reduced the limit of detection (LOD), which ranged from 0.002 to 0.008 μg/ml for the analytes, with relative standard deviations < 3 %. The correlation coefficient (R 2 ) >0.998 demonstrated high quality. In chloramphenicol eye drops, the concentration of 4-Nitrobenzaldehyde was measured to be 8.6 µg/mL below the specified concentration, with recoveries ranging from 90.0 % to 119.2 %. In comparison to existing methods, our work simplifies the pretreatment process, enhances the sensitivity and specificity of the analysis, and offers comprehensive insights into impurity detection in pharmaceutical preparations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The quantitative analysis of SJA6017, a peptide aldehyde inhibitor of calpain (Calpain Inhibitor VI), has encountered challenges in preclinical drug studies. The complex reverse-phase HPLC chromatographic behavior exhibits two peaks, each containing multiple species. An liquid chromatography-mass spectrometry (LC-MS/MS) study proposed an explanation for this phenomenon, caused by the amide aldehyde structure of SJA6017. Four chemical species corresponding to the two HPLC peaks have been identified as SJA6017 and its methyl hemiacetal, methyl enol ether, and gem-diol. In many instances of preclinical studies, methanol is favored as a substitute for DMSO. The hemiacetal is formed when the amide-activated peptide aldehyde reacts with methanol, which can then be further dehydrated in the mass spectrometer ion source under high temperature to form the methyl enol ether. The hemiacetal and gem-diol can also be decomposed to SJA6017 in the ion source. Additionally, the amide-activated peptide aldehyde can easily hydrate to the gem-diol of SJA6017 during sample incubation or sample preparation. The hemiacetal and gem-diol of SJA6017 are stable enough to have different retention times in the liquid chromatography, which explains why SJA6017 appears as two peaks, each containing multiple species. An LC-MS/MS tandem quadrupole mass spectrometer quantitative analysis method is proposed, enabling the analysis of these types of samples. This work serves as both an illustrative example and a cautionary note for mass analysis, sample incubations, and sample preparations involving compounds of peptide aldehyde, including similar aldehyde-containing metabolites, especially when methanol is present. This study provides the information needed to understand peptide aldehyde behavior at various steps of preclinical in vitro studies in the presence of methanol. It has assisted in the development of the SJA6017 bioanalysis method and will also aid in the development of bioanalysis methods for similar peptide aldehydes., (© 2024 John Wiley & Sons Ltd.)

Gas chromatography-olfactory-mass spectrometry (GC-O-MS) combined with Aroma Extract Dilution Analysis (AEDA) were employed to characterize the key odor-active compounds in sesame paste (SP) and dehulled sesame paste (DSP). The AEDA results revealed the presence of 32 and 22 odor-active compounds in SP and DSP, respectively. Furthermore, 13 aroma compounds with FD ≥ 2, OAV ≥ 1, and VIP ≥ 1 were identified as key differential aroma compounds between SP and DSP. Specifically, compounds such as 3-methylbutyraldehyde (OAV = 100.70-442.57; fruity), 2-methylbutyraldehyde (OAV = 106.89-170.31; almond), m-xylene (FD = 16; salty pastry), and 2,5-dimethylpyrazine (FD = 8-16; roasted, salty pastry) played an important role in this differentiation. Additionally, the dehulling process led to increased fermented, sweet, green, and nutty aroma notes in DSP compared to the more pronounced burnt and roasted sesame aroma notes in SP. Our findings offer a theoretical foundation for the regulation of sesame paste aroma profiles.

Heating edible oils generates aldehydes, potentially leading to adverse health effects, making their analysis essential for quality control. This study presents a convenient miniaturized kapok fiber-supported liquid-phase extraction/in-situ derivatization method for the simultaneous extraction and derivatization of aldehydes in oils. The method involves placing 150 mg oil into a 1 mL pipette tip packed with 25 mg kapok fiber, adding 150 μL ACN with 1.5 mg mL -1 DNPH, and post 30-minute static extraction, retrieving the extractant with a pipettor for liquid chromatography-tandem mass spectrometry analysis. By optimizing critical parameters through a Box-Behnken design, the method exhibits good linearity (1-500 ng g -1 , R 2  ≥ 0.991), low detection limits (0.2-1.0 ng g -1 ), excellent accuracy (95.3-107.1%) and high precisions (relative standard deviation < 7.9%). This method simplifies sample preparation processes, cuts solvent use, and facilitates automation. It effectively identifies ten aldehyde variations in six heated oils, displaying distinct profiles consistent with prior research., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Paper spray mass spectrometry (PS-MS) has evolved into a promising tool for monitoring reactions in thin films and microdroplets, known as reactive PS, alongside its established role in ambient and direct ionization. This study addresses the need for rapid, cost-effective methods to improve analyte identification in biofluids by leveraging reactive PS-MS in clinical chemistry environments. The technique has proven effective in derivatizing target analytes, altering hydrophobicity to enhance elution and ionization efficiency, and refining detection through thin-film reactions on paper, significantly expediting reaction rates by using amino acids (AAs) as model analytes. These molecules are prone to interacting with substrates like paper, impeding elution and detection. Additionally, highly abundant species in biofluids, such as lipids, often suppress AA ionization. This study employs the Schiff base (SB) reaction utilizing aromatic aldehydes for AA derivatization to optimize reaction conditions time, temperature, and catalyst presence and dramatically increasing the conversion ratio (CR) of formed SB. For instance, using leucine as a model AA, the CR surged from 57% at room temperature to 89% at 70 °C, with added pyridine during and after 7.5 min, displaying a 43% CR compared to the bulk reaction. Evaluation of various aromatic aldehydes as derivatization agents highlighted the importance of specific oxygen substituents for achieving higher conversion rates. Furthermore, diverse derivatization agents unveiled unique fragmentation pathways, aiding in-depth annotation of the target analyte. Successfully applied to quantify AAs in human and rat plasma, this reactive PS-MS approach showcases promising potential in efficiently detecting conventionally challenging compounds in PS-MS analysis.

Fruits flavor deterioration is extremely likely to occur during post-harvest storage, which not only damages quality but also seriously affects its market value. This work focuses on the study of fruits deterioration odorants during storage by describing their chemical compositions (i.e., alcohols, aldehydes, acids, and sulfur-containing compounds). Besides, the specific flavor deterioration mechanisms (i.e., fermentation metabolism, lipid oxidation, and amino acid degradation) inducing by factors (temperature, oxygen, microorganisms, ethylene) are summarized. Moreover, quality control strategies to mitigate fruits flavor deterioration by physical (temperature control, hypobaric treatment, UV-C, CA) and chemical (1-MCP, MT, NO, MeJA) techniques are also proposed. This review will provide useful references for fruits flavor control technologies development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: Quisqualis indica L. (QIL) has a long history as a traditional Chinese herb in China, but the study of volatile components in QIL from different geographical sources has been relatively rare., Objectives: To establish an optimal headspace gas chromatography-mass spectrometry (HS-GC-MS) method to comprehensively analyse the volatile component profile and screen quality markers of QIL from different origins., Methods: Response surface methodology (RSM) was used to optimise the conditions for headspace analysis. The volatile components of QIL from four main origins of southwest China were analysed and identified by HS-GC-MS. The similarity of all samples of QIL was evaluated by fingerprint. The differences of the volatile components in QIL from different origins were distinguished by chemometrics., Results: According to the optimal conditions of RSM, a total of 31 volatile components were identified, including fatty acids, aldehydes, alcohols, alkyl pyrazines, and other volatile components. Similarity evaluation presented that there were 26 common volatile components with different contents in all samples. Principal component analysis (PCA) showed that QIL from four different origins could be roughly divided into four categories. Hierarchical cluster analysis (HCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) indicated that QIL from different origins had obvious regional characteristics., Conclusion: The optimised HS-GC-MS method provided a strategy to rapidly, effectively, and accurately elucidate the volatile component profile of QIL from different origins, and seven important differential components were screened for quality evaluation and origin traceability., (© 2024 John Wiley & Sons Ltd.)

The release mechanism of flavor during caviar storage was studied by the interaction between phosvitin and four aldehydes. Gas chromatography-mass spectrometry showed that the binding rate of phosvitin with 3-methylbutanal, nonanal, (E,Z)-2,6-nonadienal, and (E)-2-octenal decreased with an increase in the aldehyde concentrations. Among them, (E,Z)-2,6-Nonadienal (0.5 mM) had the highest binding rate (84.47%). The main quenching mechanism of (E,Z)-2,6-nonadienal with phosvitin was static quenching and the binding force comprised spontaneous hydrophobic interactions. An increase in the aldehyde concentrations reduced the α-helix content of phosvitin and led to aggregation of the microstructure of phosvitin. The results of molecular docking showed that tyr residue contributed the most to the binding of phosvitin to aldehydes. This study has elucidated the mechanism of the effect of caviar protein on changes in the caviar flavor during storage and provides effective strategies for regulation of caviar flavor during storage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Aquatic products are rich in nutrients and unique in flavor, and are popular among the public. However, aquatic products are extremely susceptible to quality degradation during storage, of which odor deterioration is the most obvious and influential aspect. Odor deterioration in aquatic products is widespread and severely affects overall flavor and quality. In this study, odor deterioration and flavor-related quality degradation of tilapia during cold storage are discussed, focusing on the changes in volatile compounds and the evolution of free fatty acids (FFAs), free amino acids (FAAs), nucleotides, and microbial diversity., Results: A total of 63 volatile compounds were detected by gas chromatography-mass spectrometry, including 11 hydrocarbons, 10 alcohols, 6 aldehydes, 8 ketones, 6 esters, 9 aromatics, 3 phenols, and 10 other compounds. Microbial diversity analysis revealed that Acinetobacter, Psychrobacter, Vagococcus, and Myroides were the main dominant species of tilapia at the end of cold storage and predicted that microorganisms could influence the flavor of tilapia by participating in important metabolic pathways. Meanwhile, the evolution of FFAs, FAAs, and nucleotides also had a significant impact on odor deterioration, as evidenced by the contribution of unsaturated fatty acids (such as oleic acid and linoleic acid), Lys, and off-flavor nucleotides (HxR and Hx) to the undesirable flavor. Oxidation of oleic acid and linoleic acid resulted in changes in aldehydes, with Lys, HxR, and Hx being key flavor precursors and off-flavor contributors., Conclusion: This study contributes to a comprehensive overview of odor deterioration and the evolution of flavor-related quality in tilapia during cold storage, providing new insights into the regulation of overall flavor and quality. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Indoor air quality (IAQ) has attracted a lot of attention due to its complexity and direct effect on human health. Indoor settings in libraries entail various volatile organic compounds (VOCs) linked to the aging and degradation of print material. The effect of the storage environment on paper life expectancy was investigated by targeting the VOC emissions of old and new books using headspace solid phase micro extraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS) analysis. "Sniffing" of book degradation markers showed both ubiquitously and infrequently occurring VOCs. Old book "degradomics" revealed mostly alcohols (57%) and ethers (12%), whereas new books resulted mainly to ketones (40%) and aldehydes (21%). Chemometric processing of the results with principal component analysis (PCA) corroborated our initial observations and was able to discriminate the books by age into three groups: very old books (from the 1600 s to mid-1700), old books (from the 1800s to the early 1900s), and modern books (from the mid-twentieth century onwards) based on their gaseous markers. The measured mean concentrations of selected VOCs (acetic acid, furfural, benzene, and toluene) were below the respective guidelines set for similar places (i.e. museums). The applied non-invasive, green analytical methodology (HS-SPME-GC/MS) can assist librarians, stakeholders, and researchers to evaluate the IAQ, as well as the degree of degradation, and take the appropriate measures for book restoration and monitoring protocols., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Flaxseed milk is a plant-based dairy alternative that is rich in nutrients. Due to the low concentration of odor compounds in flaxseed milk, it cannot be completely extracted. This poses significant challenges for analysis. Therefore, this study developed a method suitable for extracting volatile compounds from flaxseed milk and compared it with three other extraction methods. It was found that Stir Bar Sorptive Extraction had the best extraction performance, identifying 39 odorants. Flavor dilution factors ranged from 1 to 512, with higher values observed for esters. 13 key odor compounds were identified (odor activity value > 1) using the external standard method for quantification; these included four aldehydes, three pyrazines, two alcohols, two esters, and two other compounds. Pyrazine compounds exhibited the highest concentrations. Aroma recombination and omission experiments showed that nine key odorants contributed significantly to the flavor profile of flaxseed milk, imparting aroma of cucumber, green, mushroom, fruity, sweet, and coconut., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study focuses on the behavior of volatile organic compounds in beef after irradiation with 1 MeV accelerated electrons with doses ranging from 0.25 kGy to 5 kGy to find reliable dose-dependent markers that could be used for establishing an effective dose range for beef irradiation. GC/MS analysis revealed that immediately after irradiation, the chemical yield and accumulation rate of lipid oxidation-derived aldehydes was higher than that of protein oxidation-derived aldehydes. The nonlinear dose-dependent relationship of the concentration of volatile organic compounds was explained using a mathematical model based on the simultaneous occurrence of two competing processes: decomposition of volatile compounds due to direct and indirect action of accelerated electrons, and accumulation of volatile compounds due to decomposition of other compounds and biomacromolecules. A four-day monitoring of the beef samples stored at 4 °C showed that lipid oxidation-derived aldehydes, protein oxidation-derived aldehydes and alkanes as well as alcohol ethanol as an indicator of bacterial activity were dose-dependent markers of biochemical processes occurring in the irradiated beef samples during storage: oxidative processes during direct and indirect action of irradiation, oxidation due to the action of reactive oxygen species, which are always present in the product during storage, and microbial-enzymatic processes. According to the mathematical model of the change in the concentrations of lipid oxidation-derived aldehydes over time in the beef samples irradiated with different doses, it was found that doses ranging from 0.25 kGy to 1 kGy proved to be most effective for beef irradiation with accelerated electrons, since this dose range decreases the bacterial content without considerable irreversible changes in chemical composition of chilled beef during storage.

The cooking fumes generated from thermal cooking oils contains various of hazardous components and shows deleterious health effects. The edible oil refining is designed to improve the oil quality and safety. While, there remains unknown about the connections between the characteristics and health risks of the cooking fumes and oils with different refining levels. In this study, the hazardous compounds, including aldehydes, ketones, polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) in the fumes emitted from heated soybean oils with different refining levels were characterized, and their health risks were assessed. Results demonstrated that the concentration range of aldehydes and ketones (from 328.06 ± 24.64 to 796.52 ± 29.67 μg/m3), PAHs (from 4.39 ± 0.19 to 7.86 ± 0.51 μg/m3), and PM (from 0.36 ± 0.14 to 5.08 ± 0.15 mg/m3) varied among soybean oil with different refining levels, respectively. The neutralized oil showed the highest concentration of aldehydes and ketones, whereas the refined oil showed the lowest. The highest concentration levels of PAHs and PM were observed in fumes emitted from crude oil. A highly significant (p < 0.001) positive correlation between the acid value of cooking oil and the concentrations of PM was found, suggesting that removing free fatty acids is critical for mitigating PM concentration in cooking fumes. Additionally, the incremental lifetime cancer risk (ILCR) values of PAHs and aldehydes were 5.60 × 10 -4 to 8.66 × 10 -5 and 5.60 × 10 -4 to 8.66 × 10 -5 , respectively, which were substantially higher than the acceptable levels (1.0 × 10 -6 ) established by US EPA. The present study quantifies the impact of edible oil refining on hazardous compound emissions and provides a theoretical basis for controlling the health risks of cooking fumes via precise edible oil processing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Effects of light or dark storage condition on the profile changes of volatile and non-volatile compounds were evaluated in dried and baked laver for 60 days. Volatile and non-volatile compounds were analyzed using gas chromatography-mass selective detection and high-performance liquid chromatography-quadrupole-time of flight-mass spectrometry, respectively. Baked laver stored in light conditions for 60 days produced the most volatile compounds, whereas dried laver stored in the dark produced the least volatile compounds. Total 11 classes of volatile compounds were detected, including alkanes, alkenes, and ketones, with aldehydes being most abundant in dried laver stored under light. Metabolite analysis of non-volatile compounds led to the selection of 12 compounds with a higher variable importance projection (VIP) value of >1.0: 6 fatty acids (VIP 1.2-2.0), 2 flavanols (VIP 1.3-1.8), hydroxybenzoic acid (VIP 1.5), hydroxycinnamic acid (VIP 2.3), a phenolic acid ester (VIP 1.9), and phloroglucinol (VIP 1.2). Generally, levels of these compounds decreased more following storage in the light than under dark, irrespective of laver preparation. The content of linolenic acid was particularly affected by storage conditions, with light conditions causing a fourfold reduction in linolenic acid level compared with dark conditions, which could result in an increased formation of aldehydes. Gallic acid and sinapinic acid were detected in dried but not baked laver, as they are destroyed by heat treatment. Therefore, laver should be baked and stored in dark conditions to prevent the development of rancidity. PRACTICAL APPLICATION: Laver is one of the representative seaweeds, and the popularity among consumers increases. Although commercially available laver is prepared in dried or baked condition, scientific studies on the changes of metabolites, including volatile and non-volatile compounds during storage, are scarce. The results of this study can be applied to improve proper storage methods to maintain the quality of laver, which can be beneficial for consumers and food industry., (© 2023 Institute of Food Technologists.)

Three different methods were used to identify and analyze the flavor of fish gelatin with different ultrafine grinding time (0, 2, 4 and 8 h). The results of electronic nose showed that overall flavor of the samples changed. HS-SPME-GC-MS identified 65 volatile compounds, including 18 aldehydes, 7 ketones, 7 alkanes, 11 alcohols, 8 esters, 7 phenols, and 7 acids. HS-GC-IMS identified 46 volatile compounds, including 21 aldehydes, 5 ketones, 5 alcohols, 6 esters, 7 acids, 1 ether, and 1 amine. The particle size analysis results indicate that the size distribution decreases from 918.97-1167.16 and 1388.81-1780.40 nm to 157.63-177.37 and 285.90-344.55 nm with the increased of grinding time. The SEM analysis results indicate that the change in flavor characteristics of FG is due to the different storage and release abilities of volatile compounds in FG with different particle sizes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The aim of this study was the optimization and validation of a green, robust, and comprehensive method for the determination of volatile carbonyl compounds (VCCs) in wines that could be added as a new quality control tool for the evaluation of a complete fermentation, correct winemaking style, and proper bottling and storage. A HS-SPME-GC-MS/MS method was optimized and automated using the autosampler to improve overall performance. A solvent-less technique and a strong minimization of all volumes were implemented to comply with the green analytical chemistry principles. There were as many as 44 VCC (mainly linear aldehydes, Strecker aldehydes, unsaturated aldehydes, ketones, and many other) analytes under investigation. All compounds showed a good linearity, and the LOQs were abundantly under the relevant perception thresholds. Intraday, 5-day interday repeatability, and recovery performances in a spiked real sample were evaluated showing satisfactory results. The method was applied to determine the evolution of VCCs in white and red wines after accelerated aging for 5 weeks at 50 °C. Furans and linear and Strecker aldehydes were the compounds that showed the most important variation; many VCCs increased in both classes of samples, whereas some showed different behaviors between white and red cultivars. The obtained results are in strong accordance with the latest models on carbonyl evolution related to wine aging.

3 S -Gluthathionylhexanal (glut3SHal) is an early precursor to the important wine aroma compound 3-sulfanylhexan-1-ol (3SH), imparting tropical passion fruit aromas, even at trace concentrations. In wine, glut3SHal occurs in equilibrium with its bisulfite adduct (glut3SH-SO 3 ), challenging its quantification. To circumvent the issues encountered when attempting to describe the equilibrium between these compounds, a method for their quantification in wine samples was developed. Separation of glut3SHal and glut3SH-SO 3 using solid-phase extraction followed by oxime derivatization and analysis via liquid chromatography-mass spectrometry allowed for measurement of both compounds in wine samples. Analysis of commercial Sauvignon Blanc wines using the developed method confirmed that glut3SH-SO 3 is the major species in the wine matrix. The method developed in this work will enable further exploration of the relationship between glut3SHal and glut3SH-SO 3 and their contribution to production of 3SH in wines. There is potential to extrapolate this work to explore other aldehyde-sulfonic acid equilibria in foods and beverages.

Sweet potato provides rich nutrients and bioactive substances for the human diet. In this study, the volatile organic compounds of five pigmented-fleshed sweet potato cultivars were determined, the characteristic aroma compounds were screened, and a correlation analysis was carried out with the aroma precursors. In total, 66 volatile organic compounds were identified. Terpenoids and aldehydes were the main volatile compounds, accounting for 59% and 17%, respectively. Fifteen compounds, including seven aldehydes, six terpenes, one furan, and phenol, were identified as key aromatic compounds for sweet potato using relative odor activity values (ROAVs) and contributed to flower, sweet, and fat flavors. The OR sample exhibited a significant presence of trans -β-Ionone, while the Y sample showed high levels of benzaldehyde. Starch, soluble sugars, 20 amino acids, and 25 fatty acids were detected as volatile compounds precursors. Among them, total starch (57.2%), phenylalanine (126.82 ± 0.02 g/g), and fatty acids (6.45 μg/mg) were all most abundant in Y, and LY contained the most soluble sugar (14.65%). The results of the correlation analysis revealed the significant correlations were identified between seven carotenoids and trans -β-Ionone, soluble sugar and nerol, two fatty acids and hexanal, phenylalanine and 10 fatty acids with benzaldehyde, respectively. In general, terpenoids and aldehydes were identified as the main key aromatic compounds in sweet potatoes, and carotenoids had more influence on the aroma of OR than other cultivars. Soluble sugars, amino acids, and fatty acids probably serve as important precursors for some key aroma compounds in sweet potatoes. These findings provide valuable insights for the formation of sweet potato aroma.

Aliphatic carboxylic acids, aldehydes, and ketones play diverse roles in microbial adaptation to their microenvironment, from excretion as toxins to adaptive metabolites for membrane fluidity. However, the spatial distribution of these molecules throughout biofilms and how microbes in these environments exchange these molecules remain elusive for many of these bioactive species due to inefficient molecular imaging strategies. Herein, we apply on-tissue chemical derivatization (OTCD) using 4-(2-((4-bromophenethyl)dimethylammonio)ethoxy)benzenaminium dibromide (4-APEBA) on a co-culture of a soil bacterium ( Bacillus subtilis NCIB 3610) and fungus ( Fusarium sp. DS 682) grown on agar as our model system. Using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), we spatially resolved more than 300 different metabolites containing carbonyl groups within this model system. Various spatial patterns are observable in these species, which indicate possible extracellular or intercellular processes of the metabolites and their up- or downregulation during microbial interaction. The unique chemistry of our approach allowed us to bring additional confidence in accurate carbonyl identification, especially when multiple isomeric candidates were possible, and this provided the ability to generate hypotheses about the potential role of some aliphatic carbonyls in this B. subtilis / Fusarium sp. interaction. The results shown here demonstrate the utility of 4-ABEBA-based OTCD MALDI-MSI in probing interkingdom interactions directly from microbial co-cultures, and these methods will enable future microbial interaction studies with expanded metabolic coverage.IMPORTANCEThe metabolic profiles within microbial biofilms and interkingdom interactions are extremely complex and serve a variety of functions, which include promoting colonization, growth, and survival within competitive and symbiotic environments. However, measuring and differentiating many of these molecules, especially in an in situ fashion, remains a significant analytical challenge. We demonstrate a chemical derivatization strategy that enabled highly sensitive, multiplexed mass spectrometry imaging of over 300 metabolites from a model microbial co-culture. Notably, this approach afforded us to visualize over two dozen classes of ketone-, aldehyde-, and carboxyl-containing molecules, which were previously undetectable from colonies grown on agar. We also demonstrate that this chemical derivatization strategy can enable the discrimination of isobaric and isomeric metabolites without the need for orthogonal separation (e.g., online chromatography or ion mobility). We anticipate that this approach will further enhance our knowledge of metabolic regulation within microbiomes and microbial systems used in bioengineering applications., Competing Interests: The authors declare no conflict of interest.

Chestnuts are known for their unique flavor and nutritional value. However, the flavor changes in chestnuts after processing remain unclear. Multi-intelligent sensory technologies and headspace solid-phase microextraction-arrow gas chromatography-mass spectrometry (HS-SPME-Arrow-GC-MS) combined with multivariate statistical analysis were applied to evaluate the effect of packaging and heat sterilization procedures on the sensory quality of chestnuts. The results showed that the significant variations (p < 0.05) between the different chestnut processing methods were revealed via the electronic eye (E-eye), electronic nose (E-nose), and electronic tongue (E-tongue). The packaging had a more significant influence on the sensory quality of the chestnuts than heat sterilization procedures. HS-SPME-Arrow-GC-MS identified 83 volatile compounds. The processed chestnuts exhibited higher aldehyde, ester, and alkene concentrations, while N 2 packaging was more favorable to flavor elicitation and retention. Therefore, combining intelligent sensory techniques with GC-MS can rapidly determine the chestnut quality and guide industrial production., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The influence of frying times (0, 2, 4, 6, 8, and 10 min) on the continuous changes in the water distribution and the concentrations of key volatile compounds in chicken breast during the frying process were studied. The fried chicken samples could be distinguished by PCA of E-nose and PLS-DA of GC-MS. A total of 40 volatile compounds were identified by GC-MS, and 28 compounds were verified to be the key compounds after further screening by OAVs. The T 22 was increased first and then decreased, while the M 22 and M 23 in fried chicken were considerably decreased and increased with increasing frying time, respectively. The content of the water and the total peak area of LF-NMR in fried chicken samples during the frying process significantly decreased, and the water was transferred from high to low degrees of freedom. In addition, water content, T 21 , T 22 , M 22 and L* value were positively correlated with most alcohols and aldehydes, and were negatively correlated with pyrazines, while a*, b*, M 23 and all amino acids were positively correlated with pyrazines and were negatively correlated with most alcohols and aldehydes. The results may guide the production processes of fried chicken and help produce high-quality chicken products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Underground shopping malls (USMs) are often open or semi-open environments with interconnected passageways, resulting in the sharing of indoor air. However, indoor air quality (IAQ) within these spaces can vary due to many diverse emission sources. We investigated the relationships between IAQ and geographical areas, as well as IAQ and store types, within USMs, in Korea. In 2020, we studied 10 different USMs, with a total of 128 outlets. We conducted comprehensive IAQ assessments (including measurements of fine particles (PM 2.5 ), aldehydes, and volatile organic compounds (VOCs)) in stores, passages, and outdoor areas. The stores were categorized into three types: clothing, fashion accessories, and food services. Additionally, we measured environmental factors such as CO 2 levels and presence of storefront walls. PM 2.5 levels were higher outdoors, whereas aldehyde and VOC levels exhibited elevations within passages and the interior of stores than in the outdoor environment. The store-to-passage ratios for PM 2.5 , individual aldehydes, and VOC concentrations ranged from 1.06 to 4.93. Formaldehyde and total VOC (TVOC) concentrations were found to be elevated in clothing and fashion accessory stores, whereas PM 2.5 concentrations were more prominent in food service establishments. Specific individual compounds, including propionaldehyde, hexaldehyde, benzene, n-heptane, toluene, n-octane, xylene, d-limonene, n-undecane, n-dodecane, and ethylbenzene concentrations exhibited associations with store types. Multivariate regression models demonstrated positive associations between most aldehydes and VOCs with CO 2 concentrations and presence of storefront walls. This study underscored variations within USMs based on area and store type. Aldehyde and VOC concentrations were notably higher in clothing and fashion accessory stores than in food service outlets; these elevations were closely linked to CO 2 levels and presence of storefront walls. These findings suggest that monitoring CO 2 levels within USM stores, optimizing air-conditioning systems, and designing future stores without storefront walls can collectively contribute to an overall improvement of IAQ within USMs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Unsaturated fatty aldehydes are the main products of fatty acid oxidation, and could be further oxidized to form volatile compounds with shorter carbon chains. Therefore, studying the oxidation of unsaturated fatty aldehydes is an important way to reveal the mechanism of food flavor formation during heating. In this study, volatile profiling of (E)-2-decenal during heating was firstly investigated by using thermal-desorption cryo-trapping combined with gas chromatography-mass spectrometry (GC-MS). A total of 38 volatile compounds were detected. Then, twenty-one reactions in the heating process of (E)-2-decenal were obtained by using density functional theory (DFT) calculations, and grouped into three oxidation pathways, namely, peroxide pathway, peroxyl radical pathway and alkoxy radical pathway. Meanwhile, the priority of these three pathways was the alkoxy radical reaction pathway > peroxide pathway > peroxyl radical reaction pathway. Moreover, the calculated results agreed well with the experimental results., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Actinidia arguta is a fruit crop with high nutritional and economic value. However, its flavor quality depends on various factors, such as variety, environment, and post-harvest handling. We analyzed the composition of total soluble sugars, titratable acids, organic acids, and flavor substances in the fruits of ten A. arguta varieties. The total soluble sugar content ranged from 4.22 g/L to 12.99 g/L, the titratable acid content ranged from 52.55 g/L to 89.9 g/L, and the sugar-acid ratio ranged from 5.39 to 14.17 at the soft ripe stage. High-performance liquid chromatography (HPLC) showed that citric, quinic, and malic acids were the main organic acids in the A. arguta fruits. Headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) detected 81 volatile compounds in 10 A. arguta varieties, including 24 esters, 17 alcohols, 23 aldehydes, 7 ketones, 5 terpenes, 2 acids, 1 Pyrazine, 1 furan, and 1 benzene. Esters and aldehydes had the highest relative content of total volatile compounds. An orthogonal partial least squares discriminant analysis (OPLS-DA) based on the odor activity value (OAV) revealed that myrcene, benzaldehyde, methyl isobutyrate, α-phellandrene, 3-methyl butanal, valeraldehyde, ethyl butyrate, acetoin, (E)-2-octenal, hexyl propanoate, terpinolene, 1-penten-3-one, and methyl butyrate were the main contributors to the differences in the aroma profiles of the fruits of different A. arguta varieties. Ten A. arguta varieties have different flavors. This study can clarify the differences between varieties and provide a reference for the evaluation of A. arguta fruit flavor, variety improvement and new variety selection.

The role played by metabolites in exhaled breath condensate (EBC) in the effect of PM on schoolchildren's pulmonary function has received little attention. Accordingly, we examined whether metabolites in EBC mediated the effect of PM 10 , PM 2.5 , and PM 1 on the pulmonary function of schoolchildren at a residential primary school who had received an air-cleaner cross-over intervention. Samples of EBC were collected from a total of 60 schoolchildren and subjected to metabolomics analysis. We found that the effect of PM on six pulmonary function indicators was mediated by the following nine lipid peroxidation-related and energy metabolism-related metabolites present in EBC: 4-hydroxynonenal, arachidoyl ethanolamide, dl-pyroglutamic acid, 5-deoxy-d-glucose, myristic acid, lauric acid, linoleic acid, l-proline, and palmitic acid. However, while all nine of these metabolites mediated the effects of PM on boys' pulmonary function, only 4-hydroxynonenal, arachidoyl ethanolamide, and dl-pyroglutamic acid mediated the effects of PM on girls' pulmonary function. Overall, our results show that (1) short-term exposure to PM affected the schoolchildren's pulmonary function by causing an imbalance between lipid peroxidation and glutathione-based antioxidant activity and by perturbing energy metabolism in respiratory system and (2) there was a sex-dependent antioxidant response to PM exposure, with boys being less resistant than girls., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023. Published by Elsevier B.V.)

The objective was to establish a robust and reliable approach for the characterisation of volatile organic compounds (VOCs) present in food contact paperboard. This was achieved through the utilisation of headspace solid-phase microextraction in tandem with comprehensive two-dimensional (2D) gas chromatography (GC) and quadrupole time-of-flight mass spectrometry (HS-SPME-GC × GC-QTOF-MS). The experimental parameters were optimised, involving the use of a DVB/C-WR/PDMS fibre at a temperature of 80 °C for a duration of 30 min. A total of 344 VOCs comprising aldehydes, ketones, alcohols, ethers, esters, alkanes and aromatic compounds, were tentatively identified in the samples. Twelve compounds believed to be from biogenic sources had a high odour impact making them major contributors to potential taint from the paperboard samples. Significant attention should be devoted to five compounds namely, 2-methylnaphthalene, 2-pentyl-furan, furfural, 1-octen-3-one and 1-octen-3-ol due to their potential adverse impact on the organoleptic qualities of packaged food items and their potential toxicity. Abbreviations: C-WR: carbon wide range; DVB: divinylbenzene; GC-MS: gas chromatography - mass spectrometry; GCxGC-QTOF-MS: comprehensive two-dimensional gas chromatography coupled to quadrupole-time-of-flight - mass spectrometry; HS-SPME: headspace - solid phase microextraction; LOD: limit of detection; LOQ: limit of quantification; OAV: odor activity values; PDMS: polydimethylsiloxane; RI: retention index; TTC: threshold of toxicological concern; VOC: volatile organic compound.

The aim of this work was to study the differentiating volatile profiles of the Spanish protected designation of origin (PDO) fortified wines obtained by headspace solid phase microextraction in conjunction with gas chromatography-mass spectrometry and powerful chemometric tools, to finally identify the marker volatile compounds most related to fortified wine types. Results revealed a satisfactory discrimination, for the first time, of the different types of PDO fortified wines, involving only a reduced number of volatile compounds selected by chemometrics. Thus, 28 volatile compounds were responsible for the differentiation according to ageing type (biological, oxidative, or mixed) resulting useful markers for the identification of each specific type of fortified wine. Among them, some esters were strongly related to biological ageing, aldehydes and acids to oxidative ageing, and lactones to mixed ageing. These volatile molecules involved in their differentiation could explain the unique organoleptic characteristics or attributes of these PDO fortified wines., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Berry thinning was applied to control crop load of "Shine Muscat" grape variety. Primary and secondary metabolites released during berries development were monitored, and the correlation between physicochemical parameters and core aroma compounds was analyzed. Results revealed a significant increase in single-berry weight and sugar-acid ratio of berries under low crop load conditions. Furthermore, phenolic content and antioxidant activity under low crop load were significantly higher than those of the other groups. Grapes with low crop loads also exhibited better aroma characteristics and higher sensory scores than those of the other groups, chiefly due to significantly increased terpene and C 13 -norisoprenoid contents and substantially decreased C 6 compound and aldehyde contents. Moreover, correlation analysis revealed total soluble solid accumulation was positively correlated to terpene accumulation, while hexanal, 2-hexanal, (E)-2-hexanal, and (E)-2-octenal were positively correlated with titratable acidity content. Thus, better grape quality could be achieved by precisely controlling berry crop load., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Cooking oil fumes (COFs) comprised of a mixture of cancer-causing volatile organic aldehydes (VOAs), particularly trans, trans-2,4-decadienal (t,t-DDE), 4-hydroxy-hexenal (4-HHE), and 4-hydroxy-nonenal (4-HNE). Monitoring toxic VOAs levels in people exposed to different cooking conditions is vital to predicting the cancer risk. For this purpose, we developed a fast tissue extraction (FaTEx) technique combined with UHPLC-MS/MS to monitor three toxic VOAs in mice lung tissue samples. FaTEx pre-treatment protocol was developed by combining two syringes for extraction and clean-up process. The various procedural steps affecting the FaTEx sample pre-treatment process were optimized to enhance the target VOAs' extraction efficiency from the sample matrix. Under the optimal experimental conditions, results exhibit good correlation coefficient values > 0.99, detection limits were between 0.5-3 ng/g, quantification limits were between 1-10 ng/g, and the matrix effect was <18.1%. Furthermore, the extraction recovery values of the spiked tissue exhibited between 88.9-109.6% with <8.6% of RSD. Cooking oil fume (containing t,t-DDE) treated mice at various time durations were sacrificed to validate the developed technique, and it was found that t,t-DDE concentrations were from 14.8 to 33.8 μg/g. The obtained results were found to be a fast, reliable, and semi-automated sample pre-treatment technique with good extraction efficiency, trace level detection limit, and less matrix effect. Therefore, this method can be applied as a potential analytical method to determine the VOAs in humans exposed to long-term cooking oil fumes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

An integrated metabolomics approach based on UPLC-QTOF-MS and HS-SPME-GC-orbitrap-MS was performed to investigate the dynamic changes of metabolite profiling in chickpeas, red speckled kidney beans, and mung beans during soaking. There were 23, 23, 16 non-volatile metabolites, and 18, 21, 22 volatile metabolites were identified as differential metabolites in chickpeas, red speckled kidney beans, and mung beans during soaking, respectively. These metabolites mainly included flavonoids, lysophosphatidylcholines (LPCs), lysophosphatidylethanolamines (LPEs), fatty acids, alcohols, aldehydes, and esters. The key time points responsible for the significant changes in metabolites and quality of the three pulses were 4, 8, and 24 h of soaking. Results revealed that the variations of some metabolites could attribute to oxidation and hydrolysis reactions. These results contribute to a better understanding of how soaking affects pulses quality, and provide useful information for determining soaking time according to nutritional and sensory requirements of their final products or dishes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The binding and release behavior of flaxseed proteins to aldehydes is significant for the sensory properties of flaxseed foods. The key aldehydes of flaxseed were selected by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) method, and the interaction between flaxseed protein and flaxseed protein was investigated by multispectral, molecular docking, molecular dynamics simulation, and particle size techniques. The results showed that 2,4-decadienal presented a higher binding capability and a higher Stern-Volmer constant with flaxseed protein than pentanal, benzaldehyde, and decanal. Thermodynamic analysis revealed that hydrogen bonding and hydrophobic interactions were the main forces. Aldehydes contributed to a certain reduction in radius of gyration (Rg) value and α-helix content of flaxseed protein. In addition, the results of particle size showed that aldehydes caused the proteins to aggregate toward larger particles. This study could provide new insights into the interactions between flaxseed food and flavor., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This study was to screen and quantify characteristic volatiles tied to the quality deterioration of reheated pork via simultaneously reheating (75 °C, 30 min) and collecting headspace volatiles of precooked pork (100 °C, 10 min; stored: 0 °C, 0-14 d) for GC-MS analysis. The concentrations of hexanal (6.05 ± 0.86-12.05 ± 0.44 mg/kg), (E)-2-octenal (1.54 ± 0.16-3.07 ± 0.08 mg/kg), (E,E)-2,4-heptadienal (1.52 ± 0.44-2.58 ± 0.31 mg/kg) and 8 other selected volatiles in reheated pork increased as the storage time of the precooked counterparts increased. The increase rate of hexanal was 2.9-199 times faster than that of other volatiles based on zero-order reaction fitting (R 2  = 0.876-0.997). Results from clustering analysis of these volatiles were consistent with their formation pathways tied to lipid autooxidation. This simple approach, reheating and collecting volatiles of precooked meat concurrently, introduces a new possibility for standardizing volatile analysis of precooked meats required being reheated before consumption., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Cantonese-style rice vinegar is one of the most important Chinese rice vinegars and is quite popular all over the southeast coast of China, especially in Guangdong. This study identified 31 volatile compounds, including 11 esters, 6 alcohols, 3 aldehydes, 3 acids, 2 ketones, 1 phenol, and 5 alkanes, using headspace solid-phase microextraction-gas chromatography-mass spectrometry. Six organic acids were detected by high performance liquid chromatography. The ethanol content was detected by gas chromatography. During acetic acid fermentation, physicochemical analysis showed that the initial concentrations of reducing sugar and ethanol were 0.0079 g/L and 23.81 g/L, respectively, and the final value of total acid was 46.5 g/L, and the pH value was stable at 3.89. High-throughput sequencing was used to identify the microorganisms, and Acetobacter, Komagataeibacter, and Ralstonia were the top three bacterial genera. Quantitative real-time polymerase chain reaction revealed patterns that were different from those of high-throughput sequencing. The co-occurrence network of microorganisms and the correlation analysis between microorganisms and flavor substances indicate that Acetobacter and Ameyamaea played crucial roles as the main functional AAB, and the failure of Cantonese-style rice vinegar fermentation can be attributed to the abnormal increase in Komagataeibacter. Microbial co-occurrence network analysis indicated that Oscillibacter, Parasutterella, and Alistipes were the top three microorganisms. Redundancy analysis disclosed that total acid and ethanol were the key environmental factors influencing the microbial community. Fifteen microorganisms closely related to the metabolites were identified using the bidirectional orthogonal partial least squares model. Correlation analysis showed that these microorganisms were strongly associated with flavor metabolites and environmental factors. The findings of this study deepen our understanding of the fermentation of traditional Cantonese-style rice vinegar., Competing Interests: Declaration of Competing Interest This work was financially supported by the National Natural Science Foundation of China (grant number 31771962). The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Schoolchildren are sensitive to airborne aldehyde exposures. The knowledge regarding inhalation exposure to aldehydes and the factors influencing exposure in schoolchildren is limited. This study aimed to assess the variability and potential health risks of exposure to aldehydes (including formaldehyde) in schoolchildren. The important factors affecting personal exposure to aldehydes were also explored. Forty schoolchildren were recruited from the urban and suburban areas of Taiwan for aldehyde samplings and questionnaire surveys. Personal and indoor home samples of aldehydes were collected simultaneously during warm and cold seasons. We also identified the potential variables associated with aldehyde exposure based on the participant's responses to the questionnaires using mixed-effects models. The dominant three abundant aldehydes identified in personal exposure samples were formaldehyde (geometric mean, GM = 12.2 µg/m 3 ), acetaldehyde (GM = 5.53 µg/m 3 ), and hexaldehyde (GM = 8.79 µg/m 3 ), accounting for approximately 80% of the total selected aldehydes. Higher personal exposure to aldehydes was observed during the warm season. Moreover, the within-subject variance was predominant, accounting for 66.6 to > 99.9% of the total variance in exposure. Schoolchildren had a high probability of overexposure to formaldehyde and acrolein, which resulted in an incremental lifetime cancer risk of 1.59 × 10 -4 (95th percentile = 4.64 × 10 -4 ). Season, location, household refurbishment, and indoor ventilation variables were significantly associated with personal exposure to aldehydes. The results can improve our understanding of aldehyde exposure among schoolchildren to propose mitigation strategies. These findings may be applied to further epidemiological studies., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Thermal pasteurization decreases the sensory quality of mandarin juice. Flavor composition was determined in four fresh-squeezed and heat-processed mandarin juice varieties using molecular sensory science approaches. The relationships between odorants and sensory profiles were analyzed, and markers for flavor deterioration were screened by multivariate statistical analysis. Seventy-four volatiles were identified, among which 36 odorants with flavor dilution factors ranging from 2 to 128 were detected by multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) coupled with aroma extract dilution analysis (AEDA). Higher intensities of cooked and off-flavor notes were observed in the heated mandarin juice, which was related to the concentration changes of the methional, methanethiol, dimethyl sulfide, and carbon disulfide by partial least squares (PLS) analysis. Ten potential markers (methional, methanethiol, dimethyl sulfide, hydrogen sulfide, β-damascenone, camphene, trans-β-ionone, decanal, d-limonene, and α-pinene) were responsible for the sensory discrimination of fresh-squeezed and heated mandarin juices., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The consumption of electronic cigarettes is a habit with an increasing prevalence, particularly among youths. Knowing the composition of e-liquids used in these devices represents the first step to understand the potential impact of e-smoking in the health of consumers. Herein, a non-target screening methodology was applied to the identification of volatile and semi-volatile compounds in a set of e-liquids from different suppliers, with different flavors, and containing different kinds of additives, such as nicotine or cannabidiol. To this end, samples were characterized by gas chromatography accurate mass spectrometry, using a time-of-flight mass analyzer. Combination of deconvoluted electronic ionization mass spectra with linear retention index values, obtained for two columns with different selectivity, permitted the identification of more than 250 chemicals with different confidence levels. Among them, respiratory pro-inflammatory compounds, acetals of propylene glycol and glycerin with aldehydes, nicotine-related and non-related alkaloids, and psychoactive cannabinoids were confirmed as concerning compounds in e-liquid samples. Concentration ratios between propylene glycol acetals and parent aldehydes varied in the range from 2% (ethyl vanillin) to more than 80% (case of benzaldehyde). The ratios between the concentrations of delta-9-tetrahydrocannabinol and cannabidiol in e-liquids stayed in the range from 0.02% to 0.3%., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Aldehyde-containing metabolites are reactive electrophiles that have attracted extensive attention due to their widespread occurrence in organisms and natural foods. Herein we described a newly-designed Girard's reagent, 1-(4-hydrazinyl-4-oxobutyl)pyridin-1-ium bromide (HBP), as charged tandem mass (MS/MS) tags to facilitate selective capture, sensitive detection and semi-targeted discovery of aldehyde metabolites via hydrazone formation. After HBP labeling, the detection signals of the test aldehydes were increased by 21-2856 times, with the limits of detection were 2.5-7 nM. Upon isotope-coded derivatization with a pair of labeling reagents, HBP-d 0 and its deuterium-labeled counterpart HBP-d 5 , the aldehyde analytes were converted to hydrazone derivatives, which generated characteristic neutral fragments of 79 Da and 84 Da, respectively. The isobaric HBP-d 0 /HBP-d 5 labeling based LC-MS/MS method was validated by relative quantification of human urinary aldehydes (slope=0.999, R 2 > 0.99, RSDs ≤ 8.5%) and discrimination analysis between diabetic and control samples. The unique isotopic doubles (Δm/z = 5 Da) by dual neutral loss scanning (dNLS) provided a generic reactivity-based screening strategy that allowed non-targeted profiling and identification of endogenous aldehydes even amidst noisy data. The LC-dNLS-MS/MS screening of cinnamon extracts led to finding 61 possible natural aldehydes and guided discovery of 10 previously undetected congeners in this medicinal plant., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The alteration of surface microstructures and chemical composition in cuticle of papaya fruit in response to chilling stress were comparatively studied between cultivars of 'Risheng' and 'Suihuang' after harvest. Fruit surface was covered by fissured wax layers in both cultivars. The presence of granule crystalloids was cultivar dependent, with higher abundance in 'Risheng' and lower in 'Suihuang'. Various typical very-long-chain aliphatics i.e., fatty acids, aldehydes, n-alkanes, primary alcohols, and n-alkenes dominated waxes; and cutin monomers were prominently 9/10,16-dihydroxyhexadecanoic acid in papaya fruit cuticle. Chilling pitting symptom was accompanied by modification of granule crystalloids into flat appearance and decreased primary alcohols, fatty acids, and aldehydes in 'Risheng', but no evident changes in 'Suihuang'. The response of cuticle to chilling injury in papaya fruit might be not directly related to the overall amount of waxes and cutin monomers, but more likely to the alteration of appearance morphologies and chemical composition in cuticle., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Zangju ( Citrus reticulata cv. Manau Gan) is the main citrus cultivar in Derong County, China, with unique aroma and flavour characteristics, but the use of Zangju peel (CRZP) is limited due to a lack of research on its peel. In this study, electronic nose, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), and partial least squares-discriminant analysis (PLS-DA) methods were used to rapidly and comprehensively evaluate the volatile compounds of dried CRZP and to analyse the role of dynamic changes at different maturation stages. The results showed that seventy-eight volatile compounds, mainly aldehydes (25.27%) and monoterpenes (55.88%), were found in the samples at four maturity stages. The contents of alcohols and aldehydes that produce unripe fruit aromas are relatively high in the immature stage (October to November), while the contents of monoterpenoids, ketones and esters in ripe fruit aromas are relatively high in the full ripening stage (January to February). The PLS-DA model results showed that the samples collected at different maturity stages could be effectively discriminated. The VIP method identified 12 key volatile compounds that could be used as flavour markers for CRZP samples collected at different maturity stages. Specifically, the relative volatile organic compounds (VOCs) content of CRZP harvested in October is the highest. This study provides a basis for a comprehensive understanding of the flavour characteristics of CRZP in the ripening process, the application of CRZP as a byproduct in industrial production (food, cosmetics, flavour and fragrance), and a reference for similar research on other C. reticulata varieties.

To investigate the main aroma-active volatiles out from comprehensive chemical profile, we proposed an aroma correlation assisted volatilome coupled network analysis strategy and applied it to the study of Rosa roxburghii. Based on 475 detected volatiles with GC × GC-TOF/MS analysis, the volatilome was screened with both positive aroma activities and high contents to discover some aliphatic acids, alcohols, aldehydes and esters, terpenoids as well as some alkenes and ketones. Especially, a series of homologous C6- and C8- acids, alcohols, aldehydes, esters as well as some terpenoids like limonene take the predominant contributions to the aromas. Moreover, two aroma-active and aroma-contributing volatile groups including acid-aldehyde-alcohol-ester and terpenoid groups were clustered to integrally be responsible for the major aromas of R. roxburghii with network analysis. Additionally, the accumulation of C6- and C8-family homologous aliphatic volatiles was also elucidated with linoleic and linolenic acid derived pathways. This strategy is practical to investigate the main aroma-active volatiles based on volatilome., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The distinctness in volatile profiles of pigmented rice with various colors (black, green, purple, red, and yellow) after puffing were assayed through gas chromatography-ion migration spectrometry (GC-IMS) to explore their odor characteristics. Fifty-two volatile components were found in those puffed rice, including 27 kinds of aldehydes (accounting for 59.69-64.37 %), 9 ketones (25.55-29.73 %), 5 alcohols (2.45-5.29 %), 4 pyrazines (1.38-2.36 %), 3 ethers (0.81-1.27 %), 2 furans (0.95-1.39 %), 1 pyridine (1.0-1,16 %), and 1 pyrrole (0.59-0.71 %). Aldehydes and ketones were the two chief volatiles in different pigmented puffed rice. These identified volatile flavor components in various pigmented puffed rice obtained by GC-IMS might be well differentiated by principal component and cluster interpretation. Meanwhile, a stable prediction model was fitted via orthogonal partial least squares-discriminant analysis, and 19 differentially volatile components were screened out based on variable importance projection (VIP) above 1. These findings could add certain information for understanding the flavor profiles of pigmented puffed rice and related products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Asphalt road paving and its subsequent complex airborne emissions have raised concerns about occupational exposures and environmental impacts. Although several studies described bitumen fumes or Polycyclic Aromatic Hydrocarbons (PAH) emissions at specific worksites, no comprehensive studies have characterised road paving emissions and identified the main determinants of exposure., Methods: A 10-year study from 2012 to 2022 was performed to examine the pollutants resulting from bitumen fume emissions and covering the main processes used in road paving (asphalt production, mechanical rolled asphalt paving, manual paving, mastic asphalt paving, emulsion paving, and coal-tar asphalt milling). A total of 623 air samples were collected at 63 worksites (on 290 workers, in the environment and near emission sources), and bitumen fumes, PAHs, aldehydes and volatile organic compounds were analysed. Biomonitoring campaigns were performed on 130 workers to assess internal exposure to PAHs., Results: Fume emissions revealed complex mixtures of C 10 -C 30 compounds, including linear saturated hydrocarbons (C 6 -C 12 ), alicyclic hydrocarbons and aliphatic ketones. PAHs were dominated by 2-3 aromatic ring compounds (naphthalene, fluorene, and phenanthrene), and C 1 -C 13 aldehydes were identified. Binder proportion, paving temperature, outdoor temperature, workload and job category influenced airborne concentrations. A significant temporal trend was observed over the time period of the study, with decreasing BF and PAH exposures. PAH biomonitoring was consistent with air samples, and urinary metabolites of 2-3 ring PAHs dominated over 4-5 ring PAHs. Occupational exposures were generally far lower than exposure limits, except coal-tar asphalt milling activities. Very low environmental concentrations were measured, which highlights a negligible contribution of paving emissions to global environmental pollution., Conclusion: The present study confirmed the complex nature of bitumen fumes and characterised the main determinants of exposure. The results highlight the need to reduce the paving temperature and binder proportion. Recycled asphalt pavement use was not associated with higher emissions. The impact of paving activities on environmental airborne pollution was deemed negligible., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The Coronavirus Disease 2019 (COVID-19) pandemic provided an unprecedented natural experiment, that allowed us to investigate the impacts of different restrictive measures on personal exposure to specific volatile organic compounds (VOCs) and aldehydes and resulting health risks in the city. Ambient concentrations of the criteria air pollutants were also evaluated. Passive sampling for VOCs and aldehydes was conducted for graduate students and ambient air in Taipei, Taiwan, during the Level 3 warning (strict control measures) and Level 2 alert (loosened control measures) of the COVID-19 pandemic in 2021-2022. Information on the daily activities of participants and on-road vehicle counts nearby the stationary sampling site during the sampling campaigns were recorded. Generalized estimating equations (GEE) with adjusted meteorological and seasonal variables were used to estimate the effects of control measures on average personal exposures to the selected air pollutants. Our results showed that ambient CO and NO 2 concentrations in relation to on-road transportation emissions were significantly reduced, which led to an increase in ambient O 3 concentrations. Exposure to specific VOCs (benzene, methyl tert-butyl ether (MTBE), xylene, ethylbenzene, and 1,3-butadiene) associated with automobile emissions were remarkably decreased by ~40-80 % during the Level 3 warning, resulting in 42 % and 50 % reductions of total incremental lifetime cancer risk (ILCR) and hazard index (HI), respectively, compared with the Level 2 alert. In contrast, the exposure concentration and calculated health risks in the selected population for formaldehyde increased by ~25 % on average during the Level 3 warning. Our study improves knowledge of the influence of a series of anti-COVID-19 measures on personal exposure to specific VOCs and aldehydes and its mitigations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Recent studies have shown that some people claim that their skin gases provoke allergy-like reactions in people in their near vicinity. Such a phenomenon or symptom is called 'people allergic to me (PATM)'. Although numerous people suffer from PATM, the actual conditions are unknown. The aim of this study was to investigate the characteristics of human skin profiles in patients with PATM by measuring the dermal emission fluxes of 75 skin gases using passive flux sampler and gas chromatography/mass spectrometry. We found common features in the human skin gas profiles of 20 subjects with PATM, with a significant difference from those of 24 non-PATM subjects: greater emissions of petrochemicals, organosulfur compounds, and some aldehydes and lower emissions of aroma compounds and others. The ratio of toluene to benzaldehyde is considered a vital sign that suggests the fundamental of PATM. These findings indicate that PATM is a medically unexplained phenomenon or symptom worthy of further research, which requires an interdisciplinary approach., (© 2023. The Author(s).)

Fenebrutinib is an orally available Bruton tyrosine kinase inhibitor. It is currently in multiple phase III clinical trials for the management of B-cell tumors and autoimmune disorders. Elementary in-silico studies were first performed to predict susceptible sites of metabolism and structural alerts for toxicities by StarDrop WhichP450™ module and DEREK software; respectively. Fenebrutinib metabolites and adducts were characterized in-vitro in rat liver microsomes (RLM) using MS3 method in Ion Trap LC-MS/MS. Formation of reactive and unstable intermediates was explored using potassium cyanide (KCN), glutathione (GSH) and methoxylamine as trapping nucleophiles to capture the transient and unstable iminium, 6-iminopyridin-3( 6H )-one and aldehyde intermediates, respectively, to generate a stable adducts that can be investigated and analyzed using mass spectrometry. Ten phase I metabolites, four cyanide adducts, five GSH adducts and six methoxylamine adducts of fenebrutinib were identified. The proposed metabolic reactions involved in formation of these metabolites are hydroxylation, oxidation of primary alcohol to aldehyde, n-oxidation, and n-dealkylation. The mechanism of reactive intermediate formation of fenebrutinib can provide a justification of the cause of its adverse effects. Formation of iminium, iminoquinone and aldehyde intermediates of fenebrutinib was characterized. N-dealkylation followed by hydroxylation of the piperazine ring is proposed to cause the bioactivation to iminium intermediates captured by cyanide. Oxidation of the hydroxymethyl group on the pyridine moiety is proposed to cause the generation of reactive aldehyde intermediates captures by methoxylamine. N-dealkylation and hydroxylation of the pyridine ring is proposed to cause formation of iminoquinone reactive intermediates captured by glutathione. FBB and several phase I metabolites are bioactivated to fifteen reactive intermediates which might be the cause of adverse effects. In the future, drug discovery experiments utilizing this information could be performed, permitting the synthesis of new drugs with better safety profile. Overall, in silico software and in vitro metabolic incubation experiments were able to characterize the FBB metabolites and reactive intermediates using the multistep fragmentation capability of ion trap mass spectrometry.

Aldehydes and ketones in urban air continue to receive regulatory and scientific attention for their environmental prevalence and potential health hazard. However, current knowledge of the health risks and losses caused by these pollutants in food waste (FW) treatment processes is still limited, especially under long-term exposure. Here, we presented the first comprehensive assessment of chronic exposure to 21 aldehydes and ketones in urban FW-air environments (e.g., storage site, mechanical dewatering, and composting) by coupling substantial measured data (383 samples) with Monte Carlo-based probabilistic health risk and impact assessment models. The results showed that acetaldehyde, acetone, 2-butanone and cyclohexanone were consistently the predominant pollutants, although the significant differences in pollution profiles across treatment sites and seasons (Adonis test, P < 0.001). According to the risk assessment results, the estimated cancer risk (CR; mean range: 1.6 × 10 -5 -1.12 × 10 -4 ) and non-cancer risk (NCR; mean range: 2.98-22.7) triggered by aldehydes and ketones were both unacceptable in most cases (CR: 37.8%-99.3%; NCR: 54.2%-99.8%), and even reached the limit of concern to CR (1 × 10 -4 ) in some exposure scenarios (6.18%-16.9%). Application of DALYs (disability adjusted life years) as a metric for predicting the damage suggested that exposure of workers to aldehydes and ketones over 20 years of working in FW-air environments could result in 0.02-0.14 DALYs per person. Acetaldehyde was the most harmful constituent of all targeted pollutants, which contributed to the vast majority of health risks (>88%) and losses (>90%). This study highlights aldehydes and ketones in FW treatments may be the critical pollutants to pose inhalation risks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Gas chromatography-ion mobility spectrometry (GC-IMS) has recently gained increasing attention for the analysis of volatile compounds due to its high sensitivity, selectivity, and robust design. Peak shape distortion, including peak tailing or broadening, are well known challenges in chromatographic analysis that result in peak asymmetry and decreased resolution. However, in IMS analysis peak tailing, which is independent on the column separation technique, have also been observed. As high boiling substances, such as monoterpenes, are mainly affected by enlarged peak tailing in GC-IMS, we propose that condensation or adsorption effects within the "cold" IMS cell, which is commonly operated at 45 °C-90 °C, are the root cause. To avoid condensation and to decrease peak tailing, we used a prototypic high temperature ion mobility spectrometry (HTIMS) in this work, which allows an increase of the IMS drift tube temperature up to 180 °C. This HTIMS was coupled to a GC column separation and used to analyse the peak shape of homologues series of ketones, alcohols, aldehydes, as well as high boiling fragrance compounds, such as monoterpenes and phenylpropanoids. While we were able to show that an increased IMS drift tube temperatures correlates well with improved peak shapes, the GC parameters of the HS-GC-HTIMS method, however, were found to have little effect on the peak shapes in IMS spectra. In particular monoterpenes, which display intense peak tailing at lower IMS drift tube temperatures, show significant improvement of the peak shape at higher IMS drift tube temperatures. This leads to the assumption that high boiling substances indeed undergo condensation effects within the IMS cell at low drift tube temperatures. For many separation tasks, such as the separation of the phenylpropanoids eugenol and isoeugenol, comparably low IMS temperatures of 120 °C are already sufficient to achieve a resolution above 1.5. However, the optimal drift tube temperature is dependent on the substance class. While the aspect ratio increases steadily for most monoterpenes, phenylpropanoids and aldehyde monomer peaks investigated, an optimal aspect ratio was found for ketones between 140 °C and 160 °C and alcohols between 120 °C and 140 °C. Lastly, the change of the reduced mobility K 0 with the increase of drift tube temperature was analysed. Compounds with similar chemical structure, such as the alcoholic monoterpenes citronellol and geraniol or the phenylpropanoids eugenol and isoeugenol show similar shifts of the K 0 value. Substances which differ in their chemical structure, such as the aldehyde monoterpenes citral and cinnamal have substantially different shifts of the K 0 value. With a future large substance database, the temperature dependant slope of the K 0 value of a substance could be used to identify the substance groups of unknown molecules. Furthermore, substances with the same drift time but different chemical composition could be separable through a change in drift tube temperature., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Medium-chain aldehydes are common human biogases that can be detected in the breath of patients with lung diseases. As such, the measurement of medium-chain aldehyde gases in human breath can provide significant, noninvasive, and diagnostic information related to the potential presence of such diseases. In this study, an analytical chip is developed for the detection of medium-chain aldehydes without interference from short-chain aldehydes. This analytical chip is composed of porous glass impregnated with pararosaniline and an acid (i.e., acetic acid with small amount of phosphoric acid). After exposure to medium-chain aldehydes, the red analytical chip became violet in color, and an absorption peak was observed at 620 nm. It was found that a non-reversible reaction occurred in the porous glass, therefore, the analytical chip functions in a cumulative manner. A linear relationship was determined between the absorbance change of the analytical chip at 620 nm and the nonanal exposure concentration. Importantly, the developed analytical chip successfully detected nonanal at concentrations of 8-270 ppb as calculated from the absorbance change at 620 nm after a 24 h exposure time. In addition, nonanal concentration was estimated using the change in the R value of the analytical chip photograph. This method is suitable for point-of-care breath analysis. Finally, the analytical chip was also found to be active toward octanal and decanal with a relative sensitivity of 0.7 compared to that of nonanal; it was not active toward short-chain aldehydes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yasuko Yamada Maruo reports financial support was provided by Futaba Electronics Memorial Foundation. Yasuko Yamada Maruo reports financial support was provided by Japan Society for the Promotion of Science. Yasuko Yamada Maruo has patent pending to Tohoku Institute of Technology., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

To investigate the flavor changes in goat meat upon storage, the volatile components observed in goat meat after different storage periods were determined using gas chromatography-ion mobility spectrometry (GC-IMS). A total of 38 volatile organic compounds (VOCs) were determined from the goat meat samples, including alcohols, ketones, aldehydes, esters, hydrocarbons, ethers, and amine compounds. 1-Hexanol, 3-Hydroxy-2-butanone, and Ethyl Acetate were the main volatile substances in fresh goat meat, and they rapidly decreased with increasing storage time and can be used as biomarkers for identifying fresh meat. When combined with the contents of total volatile basic-nitrogen (TVB-N) and the total numbers of bacterial colonies observed in physical and chemical experiments, the characteristic volatile components of fresh, sub-fresh, and spoiled meat were determined by principal component analysis (PCA). This method will help with the detection of fraudulent production dates in goat meat sales.

Aldehyde and ketone compounds are ubiquitous in the air and prone to adverse effects on human health. Cooking emission is one of the major indoor sources. Aiming to evaluate health risks associated with inhalation exposure to aldehyde and ketone compounds, 13 carbonyl compounds (CCs) released from heating 5 edible oils, 3 seasonings, and 2 dishes were investigated in a kitchen laboratory. For the scenarios of heating five types of oil, aldehydes accounted for 61.1%-78.0% of the total emission, mainly acetaldehyde, acrolein and hexanal. Comparatively, heating oil with added seasonings released greater concentrations of aldehyde and ketone compounds. The concentration enhancement of larger molecular aldehydes was significantly greater. The emission factors of aldehyde and ketone compounds for cooking the dish of chili fried meat were much greater compared to that of tomato fried eggs. Therefore, food materials also had a great impact on the aldehyde and ketone emissions. Acetone and acetaldehyde were the most abundant CCs in the kitchen. Acrolein concentrations ranged from 235.18 to 498.71 µg/m 3 , which was about 100 times greater compared to the guidelines provided by Office of Environmental Health Hazard Assessment (OEHHA). The acetaldehyde inhalation for adults was 856.83-1515.55 µg and 56.23-192.79 µg from exposure to chili fried meat and tomato fried eggs, respectively. This exceeds the reference value of 90 µg/day provided by OEHHA. The findings of this study provided scientific evidences for the roles of cooking emissions on indoor air quality and human health., Competing Interests: Declaration of Competing Interest We declare that we have no financial and personal relationships with other people or organizations that can in appropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be constructed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2022. Published by Elsevier B.V.)