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Adsorbents play a significant role in enhancing the analytical sensitivity of target analytes in complex samples by mitigating matrix effects. In our recent report, ZnO stood out among various adsorbents to determine target therapeutic drugs in complex biological matrices when applied for portable paper‐based electrospray ionization mass spectrometry (PPESI‐MS). However, the influence of the morphology of ZnO on the performance of PPESI‐MS is elusive. Herein, different morphologies of ZnO particles were prepared via co‐precipitation or ultrasonic methods, and their capability to determine different therapeutic drugs in serum were systemically investigated. The results demonstrated that flower‐shaped ZnO gave a superior capacity, and its analysis sensitivity was 2.9–12.8‐fold higher than those achieved with other ZnO morphologies. Further characterization revealed that the unique performance of flower‐shaped ZnO was closely associated with its favorable desorption behavior to drugs, small spray plume, and few spray emitters at the tip of coated paper substrate. To illustrate the potential of flower‐shaped ZnO, its coated paper was used as a substrate for the determination of various drugs in complex matrices such as serum, and a limit of detection as low as 2 pg mL−1 was achieved. The corresponding recoveries ranged from 93.2% to 107.2%. The developed protocol is promising in high‐sensitivity analysis of target drugs in complex sample matrices. [ABSTRACT FROM AUTHOR]

A novel inorganic nonmetallic material boron carbide (B4C) was applied in paper spray ionization to analyze organic molecules in both negative and positive modes. The utilization of B4C has led to a notable enhancement in signal responses for various molecules, including bisphenols and drugs, by approximately two to four times. The limit of detection (LOD) of bisphenol AF and nilotinib standard solutions can reach 1 and 0.5 μg/mL, respectively. Moreover, linear relationships for bisphenol AF was established within the concentration range of 1–100 μg/mL, exhibiting strong correlation coefficients. Recovery experiments for BPAF in water samples from the inlet and outlet of a sewage treatment plant, conducted without any pretreatment, achieved a maximum recovery rate of 98.8% and an RSD below 9.78%. [ABSTRACT FROM AUTHOR]

Food safety and authenticity analysis play a pivotal role in guaranteeing food quality, safeguarding public health, and upholding consumer trust. In recent years, significant social progress has presented fresh challenges in the realm of food analysis, underscoring the imperative requirement to devise innovative and expedient approaches for conducting on‐site assessments. Consequently, cellulose paper‐based devices (PADs) have come into the spotlight due to their characteristics of microchannels and inherent capillary action. This review summarizes the recent advances in cellulose PADs in various food products, comprising various fabrication strategies, detection methods such as mass spectrometry and multi‐mode detection, sampling and processing considerations, as well as applications in screening food safety factors and assessing food authenticity developed in the past 3 years. According to the above studies, cellulose PADs face challenges such as limited sample processing, inadequate multiplexing capabilities, and the requirement for workflow integration, while emerging innovations, comprising the use of simplified sample pretreatment techniques, the integration of advanced nanomaterials, and advanced instruments such as portable mass spectrometer and the innovation of multimodal detection methods, offer potential solutions and are highlighted as promising directions. This review underscores the significant potential of cellulose PADs in facilitating decentralized, cost‐effective, and simplified testing methodologies to maintain food safety standards. With the progression of interdisciplinary research, cellulose PADs are expected to become essential platforms for on‐site food safety and authentication analysis, thereby significantly enhancing global food safety for consumers. [ABSTRACT FROM AUTHOR]

We developed a simple, paper‐based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter‐balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part‐per‐trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On‐paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases. [ABSTRACT FROM AUTHOR]

We developed a simple, paper‐based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter‐balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part‐per‐trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On‐paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases. [ABSTRACT FROM AUTHOR]

Capturing short‐lived intermediates at the molecular level is key to understanding the mechanism and dynamics of chemical reactions. Here, we have developed a paper‐in‐tip bipolar electrolytic electrospray mass spectrometry platform, in which a piece of triangular conductive paper incorporated into a plastic pipette tip serves not only as an electrospray emitter but also as a bipolar electrode (BPE), thus triggering both electrospray and electrolysis simultaneously upon application of a high voltage. The bipolar electrolysis induces a pair of redox reactions on both sides of BPE, enabling both electro‐oxidation and electro‐reduction processes regardless of the positive or negative ion mode, thus facilitating access to complementary structural information for mechanism elucidation. Our method enables real‐time monitoring of transient intermediates (such as N,N‐dimethylaniline radical cation, dopamine o‐quinone (DAQ) and sulfenic acid with half‐lives ranging from microseconds to minutes) and transient processes (such as DAQ cyclization with a rate constant of 0.15 s−1). This platform also provides key insights into electrocatalytic reactions such as Fe (III)‐catalyzed dopamine oxidation to quinone species at physiological pH for neuromelanin formation. [ABSTRACT FROM AUTHOR]

Capturing short‐lived intermediates at the molecular level is key to understanding the mechanism and dynamics of chemical reactions. Here, we have developed a paper‐in‐tip bipolar electrolytic electrospray mass spectrometry platform, in which a piece of triangular conductive paper incorporated into a plastic pipette tip serves not only as an electrospray emitter but also as a bipolar electrode (BPE), thus triggering both electrospray and electrolysis simultaneously upon application of a high voltage. The bipolar electrolysis induces a pair of redox reactions on both sides of BPE, enabling both electro‐oxidation and electro‐reduction processes regardless of the positive or negative ion mode, thus facilitating access to complementary structural information for mechanism elucidation. Our method enables real‐time monitoring of transient intermediates (such as N,N‐dimethylaniline radical cation, dopamine o‐quinone (DAQ) and sulfenic acid with half‐lives ranging from microseconds to minutes) and transient processes (such as DAQ cyclization with a rate constant of 0.15 s−1). This platform also provides key insights into electrocatalytic reactions such as Fe (III)‐catalyzed dopamine oxidation to quinone species at physiological pH for neuromelanin formation. [ABSTRACT FROM AUTHOR]

The rise of fentanyl and fentanyl analogs in the drug supply pose serious threats to public health. Much of these compounds enter the United States through shipping routes. Here we provide a method for fentanyl screening and analysis that utilizes pressure‐sensitive adhesive (PSA) lined paper to recover drug residues from parcel‐related surfaces. The paper used is commercially available repositionable notes (also called post‐it or sticky notes). From this paper, mass spectra were obtained by paper spray‐mass spectrometry (PS‐MS), where PSA paper served as both a sampling and analysis substrate. Seven fentanyl‐related compounds were analyzed: fentanyl, 4‐anilino‐N‐phenethylpiperidine (4‐ANPP), N,1‐diphenethyl‐N‐phenylpiperidin‐4‐amine (phenethyl‐4‐ANPP), valerylfentanyl, 4‐fluoroisobutyrylfentanyl (4‐FIBF), carfentanil, and p‐fluorofentanyl. These compounds were recovered by PSA paper and identified by PS‐MS from packaging tape and plastic at 50 ng and from cardboard and shipping labels at 100 ng. The impact of cutting agents on PS‐MS analysis of fentanyl analogs was explored. No trends of analyte suppression were found at high concentrations of the cutting agents caffeine, diphenhydramine, and lidocaine when recovered from surfaces. A cartridge that required no precise cutting of PSA paper prior to sampling or analysis was evaluated for use in PS‐MS for fentanyl screening. Recovery and detection of fentanyl from plastic sheeting was demonstrated with this cut‐free cartridge. The cut‐free cartridge showed somewhat less consistency and lower analyte signal than the standard cartridge, but performance was suitable for potential screening applications. In combining PSA surface sampling with PS‐MS for drug screening, both sampling and detection of fentanyl‐related compounds is simple, rapid, and low‐cost. [ABSTRACT FROM AUTHOR]

Introduction: Distinguishing and categorizing the origin of garlic are highly significant, considering its widespread use as a flavoring agent. With billions of dollars annually in global trade, garlic is frequently susceptible to fraudulent practices. Methodology: Paper spray ionization mass spectrometry (PS‐MS) was employed to quickly analyze garlic samples from distinct geographic origins: China and Brazil. The so‐generated PS‐MS data were treated with metabolomic multivariate approaches, and the garlic samples from these different geographic regions were easily discriminated. Results: Brazilian garlic was characterized to contain higher levels of amino acids, such as arginine, proline, and valine, and organosulfur compounds, such as allicin, alliin, and l‐γ‐glutamil‐S‐allyl‐l‐cysteine, compared to Chinese garlic. The PS‐MS data were treated employing multivariate approaches, typically used in the metabolomics field, and this protocol was promptly able to discern among both types of samples. Conclusion: Hence, this combined strategy holds promise not only as an effective tool for the authentication of the geographical origin of garlic but also as a powerful means for biomarker discovery. [ABSTRACT FROM AUTHOR]

An unprecedented and direct PS‐MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS‐MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium‐contaminated, but the intensities were higher in the former samples. Moreover, long‐time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions. [ABSTRACT FROM AUTHOR]

Turmeric and ginger are extensively employed as functional ingredients due to their high content of curcuminoids and gingerols, considered the key bioactive compounds found in these roots. In this study, we present an innovative and fast method for the assay of curcuminoids and gingerols in different foods containing the two spices, with the aim of monitoring the quality of products from a nutraceutical perspective. The proposed approach is based on paper spray tandem mass spectrometry coupled with the use of a labeled internal standard, which has permitted to achieve the best results in terms of specificity and accuracy. All the calculated analytical parameters were satisfactory; accuracy values are around 100% for all spiked samples and the precision data result lower than 15%. The protocol was applied to several real samples, and to demonstrate its robustness and reliability, the results were compared to those arising from the common liquid chromatographic method. [ABSTRACT FROM AUTHOR]

The absolute dating of documents is still one of the most important challenges for forensic document examiners (FDE). The potential difference between the date on a questioned document and the actual year of production of the used paper can be only 1 to 5 years. Until now, there was no analytical method with this accuracy available. This study demonstrates a method for an absolute dating of paper by using the 14C bomb peak and dating the starch in the paper. Accelerator mass spectroscopy (AMS) radiocarbon measurements were performed on starch extracts and cellulose fibers from 50 paper samples with known production year from 1950 to 2018. For most of the paper samples, the measured 14C concentration values in the starch extracts were highly correlated with the data of the 14C bomb peak calibration curve. The differences between the calibrated ages and the actual harvest years of the starch‐containing plants were only up to 3 years. The 14C concentration in the paper fibers showed a lower but significant correlation with the production year of the papers and can be used to support the dating results of the starch extracts. In order to secure the accuracy of the dating, aside from the radiocarbon measurements of the extracted starch other analytical methods or data are used, like a detailed chemical analysis of the paper composition including fiber composition and the spectroscopic analysis of the purity of the starch extracts. In practice, only starch extracts without contaminations are used for the paper dating. [ABSTRACT FROM AUTHOR]

Criminal practices in which an individual becomes vulnerable and prone to sexual assault after ingesting drinks spiked with doping substances have become a social concern globally. As forensic protocols require a multi‐tiered strategy for chemical evidentiary analysis, the backlog of evidence has become a significant problem in the community. Herein, a fast, sensible, and complementary dual analytical methodology was developed using a single commercial paper substrate for surface‐enhanced Raman spectroscopy (SERS) and paper spray mass spectrometry (PS‐MS) analysis to identify psychotropic substances added to alcoholic beverages irrefutably. To study and investigate this criminal practice, pharmaceutical formulations containing distinct psychotropic substances (zolpidem, clonazepam, diazepam, and ketamine) were added to drinks typically consumed at parties and festivals (Pilsen beer, açaí Catuaba®, gin tonic, and vodka mixed with Coca‐Cola Zero®). A simple liquid–liquid extraction with a low‐temperature partitioning (LLE‐LTP) procedure was applied to the drinks and effectively minimized matrix effects. As a preliminary analysis, SERS spectra combined with Hierarchical Clustering Analysis (HCA) provided sufficient information to investigate the samples further. The presence of the protonated species for the psychotropic substances in the spiked drinks was readily verified in the mass spectra and confirmed by tandem mass spectrometry. Finally, the results demonstrate the potential of this methodology to be easily implemented into the routine of forensic laboratories and to be further employed at harm reduction tends at parties and festivals to detect contaminated beverages promptly and irrefutably as an efficient tool to prevent such crimes. [ABSTRACT FROM AUTHOR]

Paper spray mass spectrometry (PS‐MS) is an ambient ionization technique that allows for rapid and direct mass spectrometry analysis for a wide range of chemical compounds due to its portability, little to no sample preparation, and cost‐effective materials. As applications with this technique continue to expand, the identification and discrimination of bacteria at the strain level remain a promising avenue for researchers. Although studies in the past demonstrated the applicability of PS‐MS to discriminate bacteria at the strain level, no one has reported the strain‐level differentiation of actinobacteria without using solvent for PS‐MS. Hence, this study demonstrates that optimization of PS‐MS permits the investigation and differentiation of the metabolic profiles of actinobacteria without the need for solvents, diminishing the potential for sample contamination and consequently increasing the versatility of this technique. In doing so, strains of actinobacteria (CAAT P5–21, CAAT P5–16, CAAT 8–25, CAAT P8–92, and CAAT P11–13) were grown and transferred to produce a crude growth medium. The supernatant was used for the PS‐MS analyses using a Thermo Scientific LTQ mass spectrometer. Multivariate statistical analysis, including principal component analysis (PCA) and hierarchal cluster analysis (HCA), was employed to chemically distinguish the strains of bacteria. As a result, each strain of actinobacteria could be visually differentiated based on their metabolic profile. These findings demonstrate the practicability of using a liquid medium as an alternative to many other organic solvents when analyzing bacteria, making PS‐MS a crucial addition to a microbiologist's research toolkit. [ABSTRACT FROM AUTHOR]

Rationale: The burgeoning concern of N‐nitrosamine (NAM) contamination found in various pharmaceutical compositions has increased the demand for rapid and reliable screening methods to better assess the breadth of the problem. These carcinogenic compounds are also found in food, water, and soil, and they have been used in poison‐related homicides. Methods: A combination of complementary, ambient ionization methods, paper spray ionization (PSI) and filter cone spray ionization (FCSI)‐mass spectrometry (MS), was characterized towards trace‐level residue screening of select NAMs (e.g., N‐nitrosodimethylamine, N‐nitrosodiethylamine, N‐nitrosodibutylamine) directly from complex and problematic matrices of interest, including prescription and over‐the‐counter tablets, drinking water, soil, and consumable goods. Spectral data for analyte confirmation and detection limit studies were collected using a Thermo LCQ Fleet ion trap mass spectrometer. Results: PSI‐MS and FCSI‐MS readily produced mass spectral data marked by their simplicity (e.g., predominantly protonated molecular ions observed) and congruence with traditional electrospray ionization mass spectra in under 2 min. per sample. Both methods proved robust to the complex matrices tested, yielding ion signatures for target NAMs, as well as active pharmaceutical ingredients for analyzed tablets, flavorants inherent to food products, etc. Low part‐per‐million detection limits were observed but were shown dependent on sample composition. Conclusions: PSI‐MS and FCSI‐MS were successful in detecting trace‐level NAMS in complex liquid‐ and solid‐phase matrices with little to no prior preparation. This work suggests that these methodologies can provide a means for assessing problematic pharmaceutical adulterants/degradants for expedited quality control, as well as enhancing environmental stewardship efforts and forensic investigations. [ABSTRACT FROM AUTHOR]

Hypericum perforatum L. (St. John's wort) is one of the world's most consumed medicinal plants for treating depression and psychiatric disorders. Counterfeiting can occur in the medicinal plant trade, either due to the lack of active ingredients or the addition of substances not mentioned on the labels, often without therapeutic value or even harmful to health. Hence, 43 samples of St. John's wort commercially acquired in different Brazilian regions and other countries were analyzed by paper spray ionization mass spectrometry (PS‐MS) and modeled by principal component analysis. Hence, samples (plants, capsules, and tablets) were extracted with ethanol in a solid–liquid extraction. For the first time, PS‐MS analysis allowed the detection of counterfeit H. perforatum samples containing active principles typical of other plants, such as Ageratum conyzoides and Senna spectabilis. About 52.3% of the samples were considered adulterated for having at least one of these two species in their composition. Furthermore, out of 35 samples produced in Brazil, only 13 were deemed authentic, having only H. perforatum. Therefore, there is a clear need to improve these drugs' quality control in Brazil. [ABSTRACT FROM AUTHOR]

Rationale: Paper spray (PS) is a simple and innovative ambient ionization technique for mass spectrometry (MS) analysis. Under PS‐MS conditions, chemical reactions, which usually occur slowly on a bulk scale, are accelerated. Moreover, the formation of products and transient species can be easily monitored. In this manuscript, reactions between phthalic anhydride and diamines were conducted and monitored using a PS‐MS platform. The reaction products (phthalimides) have many pharmaceutical applications, but their traditional syntheses can take hours under reflux, requiring laborious purification steps. Methods: In situ reactions were performed by dropping methanolic solutions of phthalic anhydride and diamines on a triangular paper. The analyses were achieved by positioning the triangle tip in front of the mass spectrometer entrance, whereas a metal clip was attached to the triangle base. After adding methanol to the paper, a high voltage was applied across the metal clip, and the mass spectra were acquired. Results: The intrinsic reactivity of alkyl and aromatic diamines was evaluated. The carbon chain remarkably influenced the reactivity of aliphatic diamines. For aryl diamines, the ortho isomer was the most reactive. Moreover, for aryl amines with electron‐withdrawing substituents, no reaction was noticed. Conclusions: Taking advantage of the unique characteristics of PS‐MS, it was possible to investigate the intrinsic reactivity of model alkyl (ethylene versus propylene) and aryl (o‐phenylene versus m‐phenylene and p‐phenylene) diamines towards phthalic anhydride. Some crucial parameters that affect the intrinsic reactivity of organic molecules, such as isomerism, intramolecular interaction, and conformation, were easily explored. [ABSTRACT FROM AUTHOR]

Paper spray chemical ionization (PSCI) combined with mass spectrometry has been proposed as a sensitive method for the analysis of nonpolar aromatic compounds; however, the mechanism behind PSCI is not well understood. In the present study, the evidence for the occurrence of corona discharge is provided and its mechanism is proposed. Photographs taken with a highly sensitive camera evidently demonstrate the occurrence of corona discharge at the end of the triangular shape tip when a nonpolar solvent such as hexane was used at an applied potential of 6–7 kV. Nevertheless, corona discharge was not observed in the presence of a polar solvent. The occurrence of the corona discharge was attributed to charge accumulation in the dielectric layer generated by the nonpolar solvent on the fibers of the paper tip. Specifically, corona discharge was generated at the tip end when the charge approached a critical threshold. In the presence of a polar solvent, however, the dielectric layer was not generated and, hence, corona discharge was not observed. Based on this information, three nonpolar solvents were selected and their sensitivity for analyzing the phenanthrene and maltene fractions of crude oil was evaluated. Chlorobenzene provided the highest signal abundance; therefore, it was suggested as the optimum solvent for PSCI. Notably, the fundamental understanding of corona discharge in PSCI acquired in this study provides a basis for further improvement of this technique by way of surface modification. [ABSTRACT FROM AUTHOR]

This paper reports the use of paper spray mass spectrometry (PS‐MS) combined with chemometric models to analyze seized samples of anabolic steroids. Because many forensic laboratories typically demand high‐throughput analysis for this type of sample, we developed a quicker and simpler alternative analytical method for routine analysis with minimal sample preparation. Oily samples (n = 39) resulting from seizures carried out by Brazilian Federal and State Police units were selected for this study. These samples were analyzed by PS‐MS in the positive ion mode and full scan (50–1000 m/z), providing spectra containing patterns of the respective active ingredients present in each product. A principal component analysis (PCA) model was built, which discriminated samples mainly according to their active ingredients and allowed to detect and characterize some cases of product counterfeiting. The variable selection method ordered predictors selection was employed jointly with PCA to improve sample cluster separation and to provide model simplification. The final PCA model was built with three principal components and using only 28 spectral variables. This model accounted for 69.82% of the variance and discriminated samples according to their specific active ingredients. [ABSTRACT FROM AUTHOR]

Electrochemical reactions are better understood by gaining insight into the molecular transformations at the electrodes. This paper introduces a straightforward experimental arrangement in which the voltammetry experiment in a standard electrochemical cell integrates with online electrospray‐ionization mass‐spectrometry. The procedure allows for monitoring of the ions produced at the working electrode. The ionic species sampling is facilitated by a silica capillary embedded in the working electrode and connected directly to the electrospray ionization source. This integration configures real‐time monitoring of the ions produced at the working electrode, enhancing our knowledge of the electrochemical process. The methodology is thoroughly described and exemplified by monitoring the reactive intermediates and products that arise during the electrochemical oxidation of carbazole. This design provides an opportunity to study intermediates in electrochemical reactions with advanced mass spectrometry methods such as ion mobility separation or ion spectroscopy. [ABSTRACT FROM AUTHOR]

BACKGROUND: Baijiu is a traditional Chinese liquor produced from grains through fermentation, distillation, aging and blending. The flavor of Baijiu is influenced by factors such as raw materials, starter, processes and the environment, and since the relationship between these factors and the flavor of Baijiu is still being analyzed, the identification of different Baijiu is still somewhat difficult. In this paper, the volatile differential markers of 42 types of strong‐aroma Baijiu of different origin, alcohol content and grade were explored. RESULTS: A total of 24 volatile substances were detected by gas chromatography–electronic nose (GC‐E‐Nose) and 99 volatile substances were detected by gas chromatography–time‐of‐flight mass spectrometry (GC‐TOF MS). The peak areas of the substances obtained by GC‐E‐Nose were analyzed by the partial least squares (PLS) method, and the substances with variable importance in projection (VIP) >1 were screened out. Combined with the qualitative results of GC‐TOF MS, four substances (isobutyric acid, 2‐butanone, 2,3‐butanediol and 3‐methylbutyric acid) were selected as volatile differential markers for strong‐aroma Baijiu. An external standard curve was established to accurately quantify these four substances, and the Kruskal–Wallis test confirmed that the absolute contents of these four substances varied significantly among different samples (P < 0.01). Principal component analysis and hierarchical cluster analysis based on the absolute content of these four substances showed that different samples were prioritized for different alcohol contents. CONCLUSION: These four substances can be used as volatile differential markers of strong‐aroma Baijiu samples. This research provides theoretical support for the detection and improvement of Baijiu product quality. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

X‐ray photoelectron spectroscopy (XPS) is widely employed across various research fields due to its surface and chemical sensitivity. However, accurate interpretation poses a challenge due to the lack of comprehensive reference data in the literature, leading to misinterpretation, especially among novice users. Analyzing the chemical state of indium and indium‐containing compounds is particularly challenging due to subtle shifts in the binding energies of the commonly used 3d core line. This paper presents and discusses a collection of reference data, including the In 3d, In 3p, In 4d, In MNN, and relevant counter ion signals. Additionally, it explores other useful information such as the modified Auger parameter and Wagner (or chemical state) plots. The utility of X‐ray–induced Auger electrons is demonstrated in the speciation of mixed systems. [ABSTRACT FROM AUTHOR]

Irradiation by energetic ions, electrons, and UV photons induces sputtering and chemical processes (radiolysis) in the surfaces of icy moons, comets, and icy grains. Laboratory experiments, both of ideal surfaces and of more complex and realistic analog samples, are crucial to understand the interaction of surfaces of icy moons and comets with their space environment. This study shows the first results of mass spectrometry measurements from porous water ice regolith samples irradiated with electrons as a representative analogy to water‐ice rich surfaces in the solar system. Previous studies have shown that most electron‐induced H2 ${\mathrm{H}}_{2}$O radiolysis products leave the ice as H2 ${\mathrm{H}}_{2}$ and O2 ${\mathrm{O}}_{2}$ and that O2 ${\mathrm{O}}_{2}$ can be trapped under certain conditions in the irradiated ice. Our new laboratory experiments confirm these findings. Moreover, they quantify residence times and saturation levels of O2 ${\mathrm{O}}_{2}$ in originally pure water ice. H2 ${\mathrm{H}}_{2}$O may also be released from the water ice by irradiation, but the quantification of the released H2 ${\mathrm{H}}_{2}$O is more difficult and the total amount is sensitive to the electron flux and energy. Plain Language Summary: The surface of any airless body exposed to space is irradiated by charged and neutral particles. This irradiation can alter the surface and trigger chemical reactions (so‐called radiolysis) and is an important factor in the context of icy satellites and their environment in the solar system. This paper presents one approach to better understand these irradiation processes by irradiating porous water ice samples with electrons at laboratory conditions representative of the icy moons of Jupiter. We find that most of the radiolysis products of water leave the ice as H2 ${\mathrm{H}}_{2}$ and O2 ${\mathrm{O}}_{2}$, while some of the produced O2 ${\mathrm{O}}_{2}$ remains trapped in the irradiated ice. This could help explain remote measurements of the surfaces of Europa and Ganymede. Water may also be released from the irradiated ice. Key Points: Laboratory irradiation experiments are crucial to understand the surfaces of icy bodies in spaceFirst mass spectrometer results from water ice regolith samples irradiated with electrons are shownThe dominant radiolysis products released from the ice samples are H2 ${\mathrm{H}}_{2}$ and O2 ${\mathrm{O}}_{2}$, with a fraction of the O2 ${\mathrm{O}}_{2}$ being retained in the ice [ABSTRACT FROM AUTHOR]

Testosterone is a critical hormone involved in regulating various physiological processes in both men and women. Accurate testosterone measurement is essential for diagnosing endocrine disorders such as hypogonadism and polycystic ovary syndrome and for routine testing. Traditionally, testosterone levels are measured using serum or plasma samples, which present challenges in sample collection, storage, and transport, particularly in resource‐limited settings. Dried blood spot (DBS) sampling has emerged as an effective alternative for hormone analysis, offering significant advantages in terms of sample stability, ease of collection, and simplified logistics. This study aimed to validate a DBS‐based testosterone assay using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) to ensure accuracy and precision comparable to conventional serum‐based methods. Drops of whole blood samples were collected from adult volunteers using a single‐use safety lancet for finger pricks, with blood applied onto DBS cards (PerkinElmer 226 Spot Saver RUO card) for further analysis. The testosterone was extracted from DBS using a liquid‐liquid method and analyzed with LC‐MS/MS. The assay demonstrated excellent linearity across a wide concentration range (0.1–100 ng/mL) with a correlation coefficient (r2) of 0.999 and achieved a lower limit of detection of 0.058 ng/mL and a lower limit of quantification of 0.086 ng/mL. The method showed high precision, with intra‐ and inter‐day coefficients of variation below 10%, and satisfactory recovery rates. Hematocrit correction and matrix effect evaluations confirmed the robustness of the assay for clinical and research applications. Additionally, the assay displayed a strong clinical correlation between testosterone levels in DBS and venous serum samples, supporting its reliability for testosterone monitoring. This validation study supports that the DBS‐based LC‐MS/MS testosterone assay is a reliable tool for testosterone quantification for routine testing. [ABSTRACT FROM AUTHOR]

Rationale: Paper spray mass spectrometry (PS‐MS) was used to analyze and quantify ampicillin, a hydrophilic compound and frequently utilized antibiotic. Hydrophilic molecules are difficult to analyze via PS‐MS due to their strong binding affinity to paper substrates and low ionization efficiency, among other reasons. Methods: Solvent and paper parameters were optimized to increase the extraction of ampicillin from the paper substrate. After optimizing these key parameters, a Resolution IV 1/16 fractional factorial design with two center points was employed to screen eight different design parameters simultaneously. Results: Pore size, sample volume, and solvent volume were the most significant factors affecting average peak area under the curve (AUC) and the signal‐to‐blank (S/B) ratio for the 1 μg/mL ampicillin calibrant. After optimizing the key parameters, a linear calibration curve with a range of 0.2 μg/mL to 100 μg/mL was generated (R2 = 0.98) and the limit of detection (LOD) and lower limit of quantification (LLOQ) were calculated to be 0.07 μg/mL and 0.25 μg/mL, respectively. Conclusions: The statistical optimization procedure undertaken here increased the mass spectral signal intensity by more than a factor of 40. This statistical method of screening followed by optimization experiments proved faster and more efficient, and produced more drastic improvements than typical one‐factor‐at‐a‐time experiments. [ABSTRACT FROM AUTHOR]

Accurate quantification of disease‐signature microRNAs (miRNAs) in biomedical samples is in high demand for clinical diagnosis but still challenging because of the low abundance of miRNAs and complicating interferences in the milieus. Here, we report a multi‐amplification strategy based on paper‐spray mass spectrometry (PS MS) for the analysis of miRNAs in blood. A toehold‐mediated DNA‐strand‐displacement reaction (TSD) is employed to amplify the signal chain and to ensure the specificity. The signal chain is then cleaved by UV light to release signal molecules for detection. Moreover, the paper spray method can efficiently filter out interfering substances in the blood and further enhance the sensitivity of detection. This concept is successfully demonstrated in the prototypical detection of the cancer biomarker miRNA‐141 in blood and serum. The proposed TSD‐PS MS approach provides an efficient method for the sensitive detection of oligonucleotides at low concentration in complicated milieus. [ABSTRACT FROM AUTHOR]

Accurate quantification of disease‐signature microRNAs (miRNAs) in biomedical samples is in high demand for clinical diagnosis but still challenging because of the low abundance of miRNAs and complicating interferences in the milieus. Here, we report a multi‐amplification strategy based on paper‐spray mass spectrometry (PS MS) for the analysis of miRNAs in blood. A toehold‐mediated DNA‐strand‐displacement reaction (TSD) is employed to amplify the signal chain and to ensure the specificity. The signal chain is then cleaved by UV light to release signal molecules for detection. Moreover, the paper spray method can efficiently filter out interfering substances in the blood and further enhance the sensitivity of detection. This concept is successfully demonstrated in the prototypical detection of the cancer biomarker miRNA‐141 in blood and serum. The proposed TSD‐PS MS approach provides an efficient method for the sensitive detection of oligonucleotides at low concentration in complicated milieus. [ABSTRACT FROM AUTHOR]

In this work, we synthesized diethylamino substituted pyrazolo imine (3) fluorescent probe for recognition of Hg2+ion.The sensor probe 3 can detect Hg2+ by colorimetric method, and there is a 10‐fold enhancement in fluorescence response. When the fluorescent probe bound with Hg2+ ion, turn‐on fluorescence was observed via the coordination. Probe 3 has an excellent selectivity toward Hg2+ in the CH3CN/H2O (8:2, v/v) solution with low limit of detection and high binding association constant of 551 parts per billion (ppb) and 6.6067 × 106 m−1 for 3+Hg2+, respectively. Furthermore, the formation of 3+Hg2+ complex with 1:1 binding mode was evidenced by Job's plot, 1H NMR spectroscopy and Mass analysis. In addition, probe 3 is a feasible option to detect Hg2+ in various sources of water samples. Bio‐imaging experiments have demonstrated that probe 3 can be used to monitor Hg2+ in Escherichia coli bacterial cell. The sensor 3 was also used for paper strip application to detect Hg2+ ion. [ABSTRACT FROM AUTHOR]

Introduction: Drug checking services for harm reduction and overdose prevention have been implemented in many jurisdictions as a public health intervention in response to the opioid overdose crisis. This study demonstrates the first on‐site use of paper spray mass spectrometry for quantitative drug checking to address the limitations of current on‐site drug testing technologies. Methods: Paper spray mass spectrometry was used to provide on‐site drug checking services at a supervised consumption site in the Downtown Eastside of Vancouver, British Columbia, Canada during a 2‐day pilot test in August 2019. The method included the targeted quantitative measurement of 49 drugs and an untargeted full scan to assist in identifying unknown/unexpected components. Results: During the pilot, 113 samples were submitted for analysis, with 88 (78%) containing the client expected substance. Fentanyl was detected in 45 of 59 expected fentanyl samples, and in 50 (44%) samples overall at a median concentration of 3.6% (w/w%). The synthetic precursor of fentanyl, 4‐anilino‐N‐phenethyl‐piperidine (4‐ANPP), was found in 74.0% of all fentanyl samples at a median concentration of 2.2%, suggesting widespread poor manufacturing practices. Etizolam was detected in 10 submitted samples anticipated to be fentanyl at a median concentration of 2.5%. No clients submitting these samples expected etizolam or a benzodiazepine in their sample. In three instances, it was co‐measured with fentanyl, and in seven cases it was detected alone. Discussion and Conclusions: The quantitative capabilities and low detection limits demonstrated by paper spray mass spectrometry offer distinct benefits over existing on‐site drug checking methods and harm reduction services. [ABSTRACT FROM AUTHOR]

Rationale: The effort to make fake documents look real leads to the use of crickets and beverages to produce artificially aged papers, as land titles, based on yellowing caused by the use of these methods. An old practice in Brazil, called "cricketing", has led to the misappropriation of Brazilian land using these documents. We propose a rapid, simple, instantaneous and non‐destructive method to identify artificially aged papers by easy ambient sonic‐spray ionization mass spectrometry (EASI‐MS) analysis. Methods: Three typical aging procedures were used to obtain artificially aged papers using coffee, cola drink, and crickets, with the papers being analyzed by EASI‐MS. Multivariate statistical analyses were performed on the data to find the sample groups and to study the most relevant ions of each ageing procedure. High‐resolution MS (HRMS) was used to obtain the exact masses and attribute formulae to relevant ions present in the samples. Results: The combination of EASI‐MS and multivariate statistical analyses allowed us to identify the most relevant ions to classify the adulteration of documents and HRMS identified most of these relevant ions. TMS fingerprinting in combination with multivariate analysis also demonstrated that this approach can qualitatively differentiate all the examined paper samples. Conclusions: We developed a cheap, fast and easy method that can help to elucidate counterfeit documents that have been artificially aged, helping to identify chemical additives and one that can be used in forensic laboratories. [ABSTRACT FROM AUTHOR]

We developed a highly efficient and low‐cost organic solvents‐resistant microfluidic paper‐based analytical device (μPAD) coupled with paper spray mass spectrometry (PS‐MS) for quantitative determination of C18‐ceramide as a prognostic biomarker for several diseases. Several models of μPAD patterns have been examined to select the most resistant and efficient microchannel barriers, which can provide continuous spray at ionization zone and prevent "coffee ring" effect. Moreover, the developed μPAD has enabled the analysis of low concentration of C18‐ceramide because of the maximum supply of deposited analyte through microchannel. The MS results confirmed the formation of doubly and singly charged metal ion complexes between ceramide and different metal ions. Notably, the complexation that occurs between lithium ions and C18‐ceramide showed a high relative abundance compared with other formed complexes. Taking into account the relative abundance of complex [Cer + Li]+ at 572.8 m/z, it can be considered as a stable ion and therefore be used for the analysis of C18‐ceramide at low concentrations. Complexation of C18‐ceramide and lithium confirmed with quantum chemical calculations. The proposed method represents good linearity with a regression coefficient of 0.9956 for the analysis of C18‐ceramide and reaches a limit of detection to 0.84 nM. It has been adapted successfully for practical application in human serum samples with high recovery values in range of 92%–105%. The developed μPAD‐MS technique provides clear advantages by reducing the experimental steps and simplifying the operation process and enables to identify subnanomolar concentration of C18‐ceramide in human serum samples. [ABSTRACT FROM AUTHOR]

Recent advancements in the sensitivity of chemical instrumentation have led to increased interest in the use of microsamples for translational and biomedical research. Paper substrates are by far the most widely used media for biofluid collection, and mass spectrometry is the preferred method of analysis of the resultant dried blood spot (DBS) samples. Although there have been a variety of review papers published on DBS, there has been no attempt to unify the century old DBS methodology with modern applications utilizing modified paper and paper‐based microfluidics for sampling, storage, processing, and analysis. This critical review will discuss how mass spectrometry has expanded the utility of paper substrates from sample collection and storage, to direct complex mixture analysis to on‐surface reaction monitoring. [ABSTRACT FROM AUTHOR]

This study employs a high‐dimensional consensus mass spectral (HDCMS) similarity scoring technique to discriminate isomers collected using an electron ionization mass spectrometer. The HDCMS method was previously introduced and applied to the discrimination of mass spectra of constitutional isomers, methamphetamine and phentermine, collected with direct analysis real‐time mass spectrometry (DART‐MS). The method formulates the problem of discriminating mass spectra in a mathematical Hilbert space and is hence called "high dimensional." It requires replicate mass spectra to build a Gaussian model and evaluate the inner products between these functions. The resulting measurement variability is used as a signature by which to discriminate spectra. In this work, HDCMS is tested on electron impact ionization (EI) mass spectra of 7 terpene and terpene‐related (C10H16 and C10H14) isomers with experimental retention indices that differ by less than 30 and with traditional cosine similarity scores greater than 0.9, on a scale of 0 to 1, when compared with at least one other compound in the test set. Using identical instrument parameters, 15 replicate gas chromatography–electron ionization–mass spectrometry (GC‐EI‐MS) spectra of each isomer were collected and separated into distinct library and query sets. The HDCMS algorithm discriminated each isomer, indicating the method's potential. Because the method requires replicate measurements, observations from a simple heuristic study of the number of replicates required to discriminate these isomers is presented. The paper concludes with a discussion of compound discrimination using HDCMS and the benefits and drawbacks of applying the method to EI‐MS data. [ABSTRACT FROM AUTHOR]

Summary: Sphingolipids (SL) are bioactive compounds in milk, dairy products, and infant formula. SL has been found to have different health benefits, such as anti‐inflammatory, antimicrobial, anticancer, and cholesterol‐lowering characteristics. SL requires careful extraction, separation, and identification due to their unique characteristics. This review discusses the importance of extracting, purifying, and analysing SL from milk and dairy products. OE (Organic extraction), SPE (solid‐phase extraction), and SFE (supercritical CO2) techniques, as well as dispersive OE and SPE, are the most common methods. In addition, this review discussed various analytical techniques that can be used to determine and quantify SL classes, including TLC (thin‐layer chromatography), HPLC (high‐performance liquid chromatography), nuclear magnetic resonance spectroscopy, and mass spectrometry. These techniques are crucial for understanding the amounts of SL dairy products and infant formula. The paper also focuses on the different types of SL present in milk, dairy products, and infant formula and their concentrations. SL has the potential to be applied to the development of functional foods, and further research in this area is needed. This article sheds light on the extract, purification, and analysis of SL dairy products and infant formula, as well as their potential health benefits. [ABSTRACT FROM AUTHOR]

This article provides a personal account of the author's career in mass spectrometry, both in the United States and Spain. The author discusses their training in the US and their work with Dr. John Oró at the University of Houston, as well as their experiences with mass spectrometry and gas chromatography. They also mention their involvement in NASA research programs and the social and historic events they witnessed during their time in the US. The article then focuses on the challenges faced by the author in establishing a biomedical mass spectrometry laboratory in Spain, including the lack of support and funding for research. Despite these difficulties, the author and their team managed to publish papers and graduate students. The text also discusses the author's efforts to promote the use of biomedical mass spectrometry in Spain, including organizing international symposiums and meetings. The author reflects on the advancements in mass spectrometry technology during this time period. They also discuss their involvement in the organization of international conferences and the development of biomedical mass spectrometry in Spain. The author served on scientific committees and played a key role in organizing the 15th International Mass Spectrometry Conference in Barcelona in 2000. They also discuss the challenges and successes of their research group, including the creation of a proteomics MS lab. The author reflects on their career in the field of mass spectrometry, particularly in the medical community in Spain. They discuss the challenges they faced in conducting research and the lack of available resources and facilities. [Extracted from the article]

A bifunctional fluorescence probe (PCT) based on 2‐Hydroxy‐1‐naphthaldehyde and thiosemicarbazide was developed. The probe PCT can selectively detect Ag+ and Al3+ with two clear fluorescence color changes from colorless to yellow and blue violet, respectively. According to the Job's plots and mass spectrum, the binding stoichiometry of the probe PCT with Ag+ and Al3+ was 1 : 1, respectively. Moreover, the detection limit values of PCT for Ag+ and Al3+ in neutral solutions were 1.97 and 1.63 nM and these values were remarkably lower than allowed Ag+ and Al3+ concentrations in potable water determined by the World Health Organization (WHO). The distinct different binding mode were elucidated in this paper. Finally, the probe PCT has been used successfully for the detection of Ag+ and Al3+ in real water samples, logic gate and test paper. [ABSTRACT FROM AUTHOR]

As the food and pharmaceutical industries move toward more sustainable forms of packaging, paper is experiencing somewhat of a comeback as a packaging material. However, by its very nature paper is rich in volatiles—both with and without significant olfactory impact. Human sensory analysis has long been the benchmark for determining that a product is fit for consumer application. However, sensory analysis is limited in its application due to the high per‐sample cost. Selected ion flow tube mass spectrometry (SIFT‐MS) is an instrumental approach that has potential to rapidly screen paper samples for both sensory and chemical composition attributes in a single broad‐spectrum and sensitive analysis of volatiles. In this study, a combined approach utilizing SIFT‐MS sample analysis with multivariate statistical data processing is evaluated for its ability to distinguish between samples of different paper composition (in particular, virgin, recycled, or mixed fibres), mill of origin (manufacturing mill), sensory odour intensity rating, and sensory odour note. Paper samples from four mills were analysed using instrumental and sensory methods, together with one pulp sample. The key discriminating volatiles varied depending on the classification model but typically included hydrogen sulfide, ethanol, acetone, hexanal, dimethyl sulfide, and formaldehyde. The pulp sample generally exhibited significantly higher concentrations of volatiles—especially methanol and hydrogen sulfide. Because it was so different, it was eliminated from certain models—in particular, for determination of the mill of origin. Chemical analysis with multivariate statistical processing exhibited near‐perfect classification of the fibre type and the mill of origin. Evaluation of instrumental prediction of odour intensity rating and odour note used multivariate statistical analysis to correlate sensory and instrumental results. It was found that concentration data provided superior classification of odour intensity rating and odour note than did odour activity values (compound concentrations divided by their human odour detection thresholds [ODTs]). This result is tentatively attributed to significant uncertainties introduced by literature ODTs and the method's limit of quantitation being higher than the ODT for several compounds. When using SIFT‐MS concentration data—when coupled with multivariate statistical data processing—this preliminary study demonstrates potential for rapid, instrumental determination of the odour intensity rating and odour note traditionally determined using human sensory analysis. [ABSTRACT FROM AUTHOR]

Dried blood spot samples are simple to prepare and transport, enabling safe and accessible diagnostics, both locally and globally. We review dried blood spot samples for clinical analysis, focusing on liquid chromatography‐mass spectrometry as a versatile measurement tool for these samples. Dried blood spot samples can provide information for, for example, metabolomics, xenobiotic analysis, and proteomics. Targeted analyses of small molecules are the main application of dried blood spot samples and liquid chromatography‐mass spectrometry, but emerging applications include untargeted metabolomics and proteomics. Applications are highly varied, including analyses related to newborn screening, diagnostics and monitoring of disease progression and treatment effects of virtually any disease, as well as studies into the physiology and effects of diet, exercise, xenobiotics, and doping. A range of dried blood spot products and methods are available, and applied liquid chromatography‐mass spectrometry instrumentation is varied with regard to liquid chromatography column formats and selectivity. In addition, novel approaches such as on‐paper sample preparation (e.g., selective trapping of analytes with paper‐immobilized antibodies) are described. We focus on research papers published in the last 5 years. [ABSTRACT FROM AUTHOR]

Rationale: Chlorinated aromatics and alkanes are widely used for their flame retardancy, but they need to be monitored when used in recycled pulp. This paper reports the use of palladium acetate/activated carbon (Pa/Ac) activated by nitric acid as an online catalyst to determine chlorinated aromatics and chlorinated alkanes in recycled paper products using gas chromatography–tandem mass spectrometry (GC–MS/MS), which significantly improves the sensitivity of the method and remarkably lowers the detection limits. Methods: The Pa/Ac catalyst was prepared using a self‐made catalytic device and used as key to the online catalytic conversion of target chlorinated aromatic hydrocarbons and chlorinated alkanes for GC–MS/MS analysis. The response surface model was used to optimize catalytic conditions. Then GC–MS/MS in the multireaction monitoring mode with online catalysis was applied for the analysis of polychlorinated biphenyls, polychlorinated terphenyls, polychlorinated naphthalene, and chlorinated paraffins (CP) in recycled paper products. Results: Compared with traditional methods, the Pa/Ac catalyst can transform chlorinated aromatic hydrocarbons into aromatic hydrocarbons through dechlorination hydrogenation, thus lowering the detection limit of the GC–MS/MS method significantly. It can transform paraffin chloride into the corresponding alkane to better distinguish short‐chain, medium‐chain, or long‐chain CPs. Online catalytic conversion significantly improved the sensitivity and reproducibility (88.7%–113.1%) of the method. Tissue samples with various concentration levels of chlorinated aromatics and chlorinated alkanes were tested. The linearity range of the reduced target compounds in the reduction product solution was 0.02–1.00 μg/ml (R2 > 0.995). The quantitative detection limit was 0.03–0.05 μg/kg, and relative standard deviation was less than 6.9%. Conclusion: This study was the first to introduce the Pa/Ac catalytic device as an online catalytic unit in the determination of chlorinated aromatics and chlorinated alkanes using the GC–MS/MS method. The target compounds were converted into alkanes and aromatic hydrocarbons with unchanged carbon structures, and the method could achieve a low detection limit with no need for high‐end methods such as GC‐chemical ionization ion source (CI)‐MS or high‐resolution mass spectrometry. These methods are suitable for the determination of chlorine pollutants in recycled paper and its raw materials. [ABSTRACT FROM AUTHOR]

Paper spray ionization (PSI) is a direct, fast, and low-cost ambient ionization technique which may have clinical utility for qualitative and quantitative analysis of therapeutic drugs and metabolites from patient specimens. We developed and validated a PSI-mass spectrometry (PSI-MS/MS) method according to the US-FDA guidelines for bioanalytical studies to measure the prostate cancer drug abiraterone directly from patient plasma. The established linearity range was 3.1-156.8 ng/mL with a precision (%CV) and an accuracy (%) range of 0.5-10.7 and 93.5-103.2, respectively. The mean internal standard normalized matrix factor for abiraterone was just below 1 with highest %CV of 10.2 at the low-level quality control. In benchmarking the performance of this assay against a published LC-MS/MS assay, we showed they were mostly equivalent, with the exception of accuracy with clinical samples. We found the quantitative values observed for abiraterone measured directly from patient plasma using PSI-MS/MS showed positive bias. Upon investigation, we concluded the increased values were due to summed quantitation of isomeric abiraterone conjugates and metabolites which are separable by LC-MS/MS, but not with the current PSI-MS/MS configuration. Despite demonstrating the utility of PSI-MS/MS for rapid bioanalysis, this study also highlighted a limitation encountered with the direct analysis of abiraterone in clinical samples. [ABSTRACT FROM AUTHOR]

While nontargeted analysis aims to profile and report the relative distributions of a wide range of molecules from different lipid classes/subclasses, its major challenge is the annotation and identification of the molecules. Semitargeted analysis circumvents the problem by establishing a (potentially large) list of molecules to be targeted in the samples that are identified before the analysis. This approach is particularly adapted for lipid analysis to help with the automation of lipid annotation and identification. However, the manual extraction of peaks for many molecules and many samples is time consuming. Consequently, an automation of these extractions is deeply required. This paper presents a free R package for the automation of semitargeted analysis for lipid analysis. From raw files collected with LC‐MS device and a list of molecules to target (containing their class), it automatically returns Excel files containing the intensities for each targeted molecule and each sample. This package allows a fast computation of the intensities. Furthermore, it guarantees the reproducibility of the results and is freely available and user‐friendly. Practical Applications: With the help of the R package presented in this paper, the use of semitargeted lipidomics as an alternative to untargeted analysis should be investigated by more labs. Work on the comparisons between the approaches could be conducted. While untargeted methods are mostly used, they require long pretreatments and identification of molecules of interest. On the contrary, in semitargeted analysis, once the integration table and retention time are obtained, the results are fast and directly interpretable. An idea for lipidomics would be to use untargeted lipidomics to compute the integration table and retention table, then use semitargeted analysis for a fast computation of well identified molecules. [ABSTRACT FROM AUTHOR]

Rationale: Smoking is responsible for one in five deaths around the world. Thus, governments have been trying to reduce the number of active smokers by increasing taxes on products. This scenario creates a new problem by raising the consumption of illegally traded cigarettes, which are often seized and analyzed by police forces. Methods: Legal and illegal cigarette samples were extracted and analyzed using paper spray ionization mass spectrometry (PS-MS). The mass spectrometer was set to operate in full-scan positive ion mode to yield representative chemical profiles of each sample. The results were used to build a chemometric model using partial least squares discriminant analysis (PLS-DA) to discriminate between both sets of samples, i.e. legal and illegal. Results: The PS-MS procedure was fast, simple and efficient, yielding high-quality and reproducible mass spectra with a very good signal-to-noise ratio. Even though all samples displayed visually indistinguishable mass spectra, the PS-MS data handled by the PLS-DA approach furnished a model that reached sample classification with rates of 100% and 80% for the training and validation sets, respectively. Conclusions: A novel methodology was successfully developed associating the PSMS technique with chemometric analysis to differentiate between legal and illegal cigarettes. The PS-MS technique proved to be adequate for obtaining fingerprints of such types of samples despite high complexity, and a PLS-DA model was successfully constructed achieving 82.1% accuracy. [ABSTRACT FROM AUTHOR]

Dried blood spot (DBS) analysis has been an inherent part of sports drug testing through the technological advancements of the past decade. Trimetazidine, a non‐threshold banned substance, is excreted into urine after a dose of the permitted drug lomerizine. Therefore, a lomerizine‐specific metabolite (M6) is analyzed to confirm the origin of trimetazidine in traditional urine analysis. Application studies were conducted to develop an analytical method for trimetazidine applicable to DBS. These studies comprise (1) the effect of different sampling sites on the detection of trimetazidine, (2) the determination of the appropriate trimetazidine level required for DBS analysis, and (3) differentiating between trimetazidine and lomerizine use. A high‐resolution mass spectrometric method for detecting trimetazidine in DBS was validated. After oral administration of trimetazidine (n = 7), venous and capillary blood (fingertip and upper arm) were spotted on cellulose paper. Trimetazidine could be identified in DBS in all subjects up to 60 h after administration. The limit of detection was 0.05 ng/ml, and the limit of identification was 0.06 ng/ml, suggesting the minimum required performance level of 0.2 ng/ml. In the fingertip capillary blood, biases of 9.7% (vs. upper arm) and 13.0% (vs. vein) were observed in the trimetazidine intensity; however, there were no concerns in the qualitative analysis. After administering lomerizine (n = 10), the intact lomerizine has a strong peak intensity in blood compared to trimetazidine. Contrary to urine analysis, the M6 was less detectable in blood. Laboratories should confirm intact lomerizine whenever trimetazidine is identified in DBS. [ABSTRACT FROM AUTHOR]

Omarigliptin (OMG) is an antidiabetic drug indicated for the treatment of type 2 diabetes mellitus. Forced degradation studies are practical experiments to evaluate the stability of drugs and to establish degradation profiles. Herein, we present the investigation of the degradation products (DPs) of OMG formed under various stress conditions. OMG was subjected to hydrolytic (alkaline and acidic), oxidative, thermal, and photolytic forced degradation. A stability‐indicating ultra‐fast liquid chromatography method was applied to separate and quantify OMG and its DPs. Five DPs were adequately separated and detected in less than 6 min, while other published methods detected four DPs. MS was applied to identify and obtain information on the structural elucidation of the DPs. Three m/z DPs confirmed previously published research, and two novel DPs were described in this paper. The toxicity of OMG and its DPs were investigated for the first time using in vitro cytotoxicity assays, and the sample under oxidative conditions presented significant cytotoxicity. Based on the results from forced degradation studies, OMG was found to be labile to hydrolysis, oxidation, photolytic, and thermal stress conditions. The results of this study contribute to the quality control and stability profile of OMG. [ABSTRACT FROM AUTHOR]

Rationale: Atmospheric pressure matrix‐assisted laser desorption/ionization (AP‐MALDI) mass spectrometry has enabled the untargeted analysis and imaging of neuropeptides and proteins in biological tissues under ambient conditions. Sensitivity in AP‐MALDI can be improved by using sample‐specific preparation methods. Methods: A comprehensive and detailed optimization strategy including instrument parameters, matrix spraying and sample tissue washing pretreatment was implemented to enhance the sensitivity and coverage of neuropeptides in mouse pituitary tissues by commercial AP‐MALDI mass spectrometry imaging (MSI). Results: The sensitivity of a commercial AP‐MALDI system for endogenous neuropeptides in mouse pituitary was enhanced by up to 15.2‐fold by shortening the transmission gap from the sample plate to the inlet, attaching copper adhesive tape to an indium tin oxide‐coated glass slide, optimizing the matrix spray solvent and using sample tissue washing pretreatment. Following careful optimization, the distributions of nine endogenous neuropeptides were successfully visualized in the pituitary. Furthermore, the quantitative capability of AP‐MALDI for neuropeptides was evaluated and the concentrations of neuropeptides oxytocin and vasopressin in the pituitary posterior lobe were increased approximately twofold under hypertonic saline stress. Conclusion: Mouse pituitary neuropeptides have emerged as important signaling molecules due to their role in stress response. This work indicates the potential of modified AP‐MALDI as a promising AP MSI method for in situ visualization and quantification of neuropeptides in complex biological tissues. [ABSTRACT FROM AUTHOR]

This paper covers direct sub‐atmospheric pressure ionization mass spectrometry (MS). The discovery, applications, and mechanistic aspects of novel ionization processes for use in MS that are not based on the high‐energy input from voltage, laser, and/or high temperature but on sublimation/evaporation within a region linking a higher to lower pressure and modulated by heat and collisions, are discussed, including how this new reality has guided a series of discoveries, instrument developments, and commercialization. A research focus, inter alia, is on how best to understand, improve, and use these novel ionization processes, which convert volatile and nonvolatile compounds from solids (sublimation) or liquids (evaporation) into gas‐phase ions for analysis by MS providing reproducible, accurate, sensitive, and prompt results. Our perception on how these unprecedented versus traditional ionization processes/methods relate to each other, how they can be made to coexist on the same mass spectrometer, and an outlook on new and expanded applications (e.g., clinical, portable, fast, safe, and autonomous) is presented, and is based on ST's Opening lecture presentation at the Nordic Mass spectrometry Conference, Geilo, Norway, January 2023. Focus will be on matrix‐assisted ionization (MAI) and solvent‐assisted ionization (SAI) MS covering the period from 2010 to 2023; a potential paradigm shift in the making. [ABSTRACT FROM AUTHOR]

Purpose: The management of blepharitis continues to challenge clinicians due to the poorly understood aetiology of the condition. We recently identified the family of intracellular plakin proteins as essential driving forces underlying anterior blepharitis. A large‐scale protein analysis was used to study if a topical dexamethasone/tobramycin solution could be used to reverse the expression of plakin proteins. Methods: Tear film samples from treatment naïve patients with anterior blepharitis (n = 15) were collected with Schirmer filtration paper. A subgroup of the patients (n = 10) received treatment with a dexamethasone/tobramycin 1 + 3 mg/mL ophthalmic suspension (Tobradex®) for 3 weeks and collection of tear film samples was repeated. The samples were analysed with label‐free quantification nano liquid chromatography–tandem mass spectrometry requiring quantification in at least 70% of the samples in each group. Proteins were considered differentially expressed if p < 0.05. Results: Following Tobradex® intervention, 27 proteins were upregulated while 61 proteins were downregulated. Regulated proteins after Tobradex® treatment were involved in intermediate filament cytoskeleton organization including downregulation of the plakin proteins envoplakin, epiplakin and periplakin. Plectin, a protein of the plakin family, remained unchanged after Tobradex® therapy. Tobradex® treatment resulted in the regulation of proteins involved in translation including a cluster of downregulated ribosomal proteins. Tobradex® intervention was associated with the regulation of proteins involved in fructose metabolism and glycolytic processes including fructose‐1.6‐bisphosphatase 1, fructose‐bisphosphate aldolases A and B, pyruvate kinase PKM and transketolase. Ig lambda chain V‐I region, prominin‐1, and protein Niban were upregulated after Tobradex® treatment. Conclusions: Tobradex treatment reversed the expression of plakin proteins in anterior blepharitis. Topical solutions which inhibit the expression of plakin proteins may have the potential to restore the ocular surface integrity in anterior blepharitis and should be explored further. [ABSTRACT FROM AUTHOR]

Summary: Monitoring and localizing molecules on living plants is critical for understanding their growth, development and disease. However, current techniques for molecular imaging of living plants often lack spatial information or require tedious pre‐labelling. Here, we proposed a novel molecular imaging platform that combines sliver nanowire‐doped Ti3C2 MXene (Ag NWs@MXene) flexible film substrate with laser desorption/ionization mass spectrometry imaging (AMF‐LDI‐MSI) to study the spatial distribution of biomolecules on the surface of living plants. This platform overcomes the MSI challenges posed by difficult‐to‐slice plant tissues (e.g., tough or water‐rich roots and fragile flowers) and enables precisely transfer and visualize the molecule. Comparisons of the measurement results to those from matrix‐assisted LDI‐MSI (MALDI‐MSI) technology demonstrate the accuracy and reliability of the platform. Biocompatibility evaluations indicated that the platform without observable adverse effects on the health of living plants. The distribution of growth and disease‐associated signalling molecules, such as choline, organic acids and carbohydrates, can be in situ non‐destructively detected on the surfaces of living plants, which is important for tracking the health of plants and their diseased areas. AMF‐LDI‐MSI platform can serve as a promising tool for label‐free, in situ and non‐destructive monitoring of functional biomolecules and plant growth from a spatial perspective. [ABSTRACT FROM AUTHOR]

The dried root of Sophora davidii Kom. ex Pavol (Leguminosae, family) is a folk medicine and has long been used for the treatment of various diseases, including cough, hematochezia, sore throat, and dysentery. In this study, UHPLC‐Q‐Exactive Orbitrap mass spectrometry investigations were applied to obtain the profiling of the flavonoids in S. davidii. Finally, 108 compounds were identified, and 85 of them were firstly reported. Then, the in vitro antioxidant activity and tyrosinase activity of S. davidii were investigated using the DPPH radical scavenging ability, hydroxyl radical scavenging, and copper‐reducing ability method and by measuring the rate of tyrosinase‐catalyzed L‐dopa oxidation. To our knowledge, this is the first study of S. davidii's antioxidant activity, anti‐tyrosinase activity, and systematic characterization of flavonoids. The current study will be of support for the usage of S. davidii in the future development of the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

The accumulation of senescent cells is thought to play a crucial role in aging‐associated physiological decline and the pathogenesis of various age‐related pathologies. Targeting senescence‐associated cell surface molecules through immunotherapy emerges as a promising avenue for the selective removal of these cells. Despite its potential, a thorough characterization of senescence‐specific surface proteins remains to be achieved. Our study addresses this gap by conducting an extensive analysis of the cell surface proteome, or "surfaceome", in senescent cells, spanning various senescence induction regimes and encompassing both murine and human cell types. Utilizing quantitative mass spectrometry, we investigated enriched cell surface proteins across eight distinct models of senescence. Our results uncover significant changes in surfaceome expression profiles during senescence, highlighting extensive modifications in cell mechanics and extracellular matrix remodeling. Our research also reveals substantive heterogeneity of senescence, predominantly influenced by cell type and senescence inducer. A key discovery of our study is the identification of four unique cell surface proteins with extracellular epitopes. These proteins are expressed in senescent cells, absent or present at low levels in their proliferating counterparts, and notably upregulated in tissues from aged mice and an Alzheimer's disease mouse model. These proteins stand out as promising candidates for senotherapeutic targeting, offering potential pathways for the detection and strategic targeting of senescent cell populations in aging and age‐related diseases. [ABSTRACT FROM AUTHOR]