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Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: A simple check test method was designed to confirm whether a 2,4‐dinitrophenylhydrazine (DNPH) filter for formaldehyde can be used to measure other compounds. Methods: Sample mixtures containing the same concentrations of formaldehyde, acetaldehyde, and acetone were spiked to the DNPH‐filter, extracted, and then measured using high performance liquid chromatography with photodiode array detector (HPLC‐PDA). The amounts of DNPH‐derivatives versus the amounts of spiked samples were then plotted. Results: When the amount of DNPH << the total amount of spiked samples, the amount of DNPH‐derivatives was formaldehyde > acetaldehyde >> acetone. This order corresponded to the relative rate constants for the reaction. Therefore, this study confirmed that acetone was not collected at the formaldehyde sampling rate. Conclusions: This check test easily measured the reaction rate order and can be used as a simple test to determine whether other samples can be measured by the analytical methods used for the specified sample. [ABSTRACT FROM AUTHOR]

Copyright of Tobacco Science & Technology is the property of Tobacco Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• MS detection improves dynamic range and sensitivity compared to ELSD and CAD. • Raw material impurities can transfer to drug substances in lipid nanoparticle therapies. • Hydrazone derivatization increases assay sensitivity for detection of aldehydes. • Aldehyde impurities above regulatory thresholds pose a risk to mRNA payloads. Lipid nanoparticles (LNPs) are designed to protect and transport sensitive payloads or active pharmaceutical ingredients as part of new therapeutic modalities. As a multi-component particle, a high degree of quality control is necessary to ensure raw materials are free of critical impurities that could adversely impact the drug product. In this study, we demonstrate a reversed phase liquid chromatography method hyphenated with a single quadrupole mass spectrometer (RPLC-MS) as an alternative platform to methods that incorporate evaporative light scattering or charged aerosol detectors in the detection and quantitation of critical impurities associated with LNPs. The proposed RPLC-MS method offers an increase of up to 2 orders of magnitude in dynamic range and 3 orders of magnitude in sensitivity in the analysis of impurities associated with LNPs compared to conventional detectors. Access to complementary mass data enabled the detection and identification of stability indicating impurities as part of stress studies carried out on an ionizable lipid. In addition to confirmation of peak identity, complementary mass data was also used to assess residual aldehydes in raw material and formulated LNPs in accordance with regulatory guidance. Following derivatization using 2,4-dinitrophenylhydrazine, aldehyde content in the ionizable lipid raw material was determined to exceed the reporting threshold of 0.05% in 30% of the test cases. The experimental findings observed in this study demonstrate the utility of the proposed RPLC-MS method in the identification and monitoring of stability-indicating attributes associated with LNPs as part of current Good Manufacturing Practices for improved consumer safety in drug products. [ABSTRACT FROM AUTHOR]

Ultraviolet treatment (UV-C) is well known for its antimicrobial effects and current research shows that it has the potential to inactivate microorganisms in milk at much lower temperatures than conventional thermal treatment. However, Ultraviolet irradiation may result in adverse effects on milk quality, which arises due to photo oxidation in the presence of oxygen. Limiting the dissolved oxygen content in milk can minimize oxidative damage and thus, result in a better product quality. Nitrogen purging could be an effective method for reducing dissolved oxygen from liquids. The present study evaluates effects of nitrogen purging (prior to UV treatment) on milk quality. It was found that nitrogen purged UV treated milk causes minimal changes to physicochemical properties of milk. [ABSTRACT FROM AUTHOR]

2,4-Dinitrophynylhydrazine and two thiocyanate ions in a (M:L1:L2) 1:2:2 molar ratio was synthesized in the complexes of Co(II) and Ni(II). The prepared compounds were identified through a C.H.N.S. analysis, conductivity measurements, powder X-ray diffraction (PXRD), the infrared spectrum, and a UV-visible spectrum analysis, in addition to the magnetic properties being measured. The measurements of the molar conductance implieda nonelectrolytic nature of compounds Co(II) and Ni(II). The magnetic susceptibility, as well as electronic spectra, represented all the metal complexesthroughoctahedral geometry, respectively. The PXRD patterns suggested that all the complexes were an orthorhombic system with unit cell parameters. The in-vitro biological activity of the ligand and the metal complexes were screened against the Gram-positive and negative pathogenic bacteria Staphylococcus aureus, Bacillus subtilis, Pseudomonas, aeruginosa and Escherichia coli, as well as the fungal species of Aspergillusniger and Candida albicans.Thus, the metal complexes showeda high efficiency of antimicrobial activity compared with the ligand. Furthermore, applications of the ligand, as well as the metal complexes, were tested for in-vitro antioxidant potential in aDPPH assay. The results showed that the activity of the metal complexes with the in-vitro antioxidant was more active than that of 2,4-dinitrophenylhydrazine(DNPH).

Abstract The analysis of trace carbonyls including aldehydes and ketones is important for monitoring environmental air quality, determining toxicity of aerosol of electronic cigarette, and detecting diseases by breath analysis. This work reports investigation of a single microreactor chip with HClO 4 -acidified DNPH coating for capture and analysis of carbonyls in air and exhaled breath. Three aldehydes and three ketones were spiked into one liter synthetic air in Tedlar bags serving as gaseous carbonyl standard for characterization of capture efficiency (CE). The HClO 4 -acidified DNPH showed higher CE of carbonyls than conventionally-used acid including H 3 PO 4 and H 2 SO 4 acidified DNPH under the microreactor conditions. The microreactor conditions including HClO 4 to DNPH molar ratio, DNPH to carbonyls molar ratio, and gaseous sample flow rate through the microreactor were studied in detail and thereby optimized. Under the optimized conditions, 100% of CEs for aldehydes and above 80% for ketones were obtained. The microreactor chips were applied to determine acetone concentration in exhaled breath. Highlights • An efficient method for capture of trace concentrations of gaseous carbonyls • A single microreactor chip for capture carbonyls in air • HClO 4 -acidified DNPH was coated on the surface of the micropillars of microreactor chip. • 100% CEs for aldehydes and over 80% CEs for ketones were obtained under optimized microreactor chip conditions. [ABSTRACT FROM AUTHOR]

Acetone is a human biogas and is widely used in industrial manufacturing. Acetone can be detected in the breath of diabetic patients, and the measurement of acetone in human breath provides significant, non-invasive, diagnostic information on a patient's diabetic condition. An analytical chip for detecting acetone was developed herein. The analytical chip was composed from porous glass impregnated with 2,4-dinitrophenylhydrazine (DNPH) and hydrochloric acid. The analytical chip before exposure to acetone and the reaction product between acetone and DNPH (Acetone-DNPH) showed an absorption peak at 349 nm and 359 nm, respectively. The molar absorption coefficient of Acetone-DNPH in the porous glass at 359 nm was 1.57 times larger than that of DNPH. Based on these results, the percentage of reaction ([Acetone-DNPH] t /[DNPH] 0 ) could be calculated using the absorbance values at 359 nm. The logarithm of the percentage of reaction was correlated with the cumulative acetone concentration, which was a product of an exposed acetone concentration and an exposure time. The developed analytical chip was active in the cumulative acetone concentration range from 0.53 ppm × hour to 20 ppm × hour, and was functional in an atmosphere with 30%–90% relative humidity (R.H.). [ABSTRACT FROM AUTHOR]

The crude palm oil (CPO) and refined palm oil (PO) not only have a balance of saturated and unsaturated fatty acids but also have the highest β-carotene and vitamin E compared to others vegetable oils. A series of aliphatic aldehydes starting from hexanal to decanal was identified by LC-MS/MS and quantified as DNPH derivatives. In addition, the total amount of carbonyls was determined based on the calibration with hexanal. Looking at the kinetic profile of the carbonyl formation in crude palm oil and refined palm oil, both of the oils were still stable until 10 h of oxidation with the Ranzimat at 120 °C.The analytical method for quantifying the vitamin E and β-carotene are quick, reliable, precise, economical and suitable for the routine analysis. For both analyses, a simple dilution of the oil was necessary. The quantitative analysis showed that β-carotene in the oxidized crude palm oil decreased from 2.34 mg/g to 0.33mg/g within 7.5 h of oxidation. However, after 7.5 h, no more β-carotene was detected. In addition, β-carotene was not detected in refined palm oil. The HPLC-DAD method developed for the β-carotene in the crude palm oil was validated. The coefficient of determination (0.999) of the linear regression indicates a good correlation between the peak area and the amount of β-carotene. The linearity of the β-carotene analysis was tested in the range 0.00078-0.05 μg/cm3. The limit of detection (LOD) was 2.65 μg/cm3 and the limit of quantification (LOQ) was 8.83 μg/cm3 for β-carotene.Vitamin E in both refined and crude palm oil, δ-tocotrienol and γ-tocotrienol, have the long shelf life compared to α-tocopherol and γ-tocopherol. The δ-tocotrienol is degraded slowly and can be found even after 15 h of oxidation with 0.035 mg/g remaining in the oxidized crude palm oil. However, in refined palm oil, the δ-tocotrienol could be determined until 11 h of oxidation with 0.49 mg/g. [ABSTRACT FROM AUTHOR]

A sensitive, cost-effective, reproducible high-performance liquid chromatography method was developed and validated for quantitative determination of acetaldehyde in candesartan cilexetil using the concept of threshold of toxicological concern. Acetaldehyde is reacted with 2,4-dinitrophenylhydrazine to form a Schiff base product with an absorbing maximum at 364 nm. Effective chromatographic separation was achieved on an Inertsil ODS 3V, 250×4.6 mm, 5 μm column with a mobile phase of 40:60 v/v water and acetonitrile and at a flow rate of 1.0 ml/min. The column temperature was controlled at 25° and the injection volume was 30 μl. These conditions resolved the dinitrophenylhydrazine-acetaldehyde product with unreacted dinitrophenylhydrazine, the drug substances and related impurities, as well as diluent peak within 20 min. The retention time of dinitrophenylhydrazine-acetaldehyde product was approximately 10.6 min. The method was linear, accurate, precise, specific, rapid and found suitable for this analysis. [ABSTRACT FROM AUTHOR]

A relation between oil uptake and cancer as well as induction of hepatic inflammation was shown earlier. It is discussed that the main oil oxidation products-hydroperoxides and carbonyls-might be the reason for the mentioned diseases. In this manuscript quantitative determination of aldehydes which are formed during oxidation of triolein-as a model substance-using the Rancimat 679 is described. The oxidation of 11 g of triolein is carried out at 120 °C sparging air with a flow of 20 dm/h for 10 h. A series of aliphatic aldehydes starting from hexanal to decanal as well as decenal was identified by LC-MS/MS and quantified as DNPH derivatives. In addition, the total amount of carbonyls was determined. Based on the calibration with hexanal, all other dominant substances were in the similar concentration range with maximum concentrations of 1.6 µmol/cm of hexanal, 2.3 µmol/cm of heptanal, 2.5 µmol/cm of octanal, 3.2 µmol/cm of nonanal, 4.0 µmol/cm of decanal after 6 h. The total amount of carbonyls reached a maximum after 6 h being 27 µmol/cm for triolein without antioxidant. The results of this investigation will be a basis for further toxicological studies on oxidized oils. Graphical abstract: [ABSTRACT FROM AUTHOR]

A selective method based on derivatization with 2,4-dinitrophenylhydrazine (DNPH) is described for the determination of several carbonyl compounds. The factors affecting the derivatization reaction of aldehyde and DNPH were investigated. The product of the derivatization reaction has been characterized by UV/Vis spectrophotometry, NMR, infrared spectroscopy and cyclic voltammetry. Then, an electrochemical study for the determination of aldehyde-2.4-dinitrophenylhydrazone was performed at glassy carbon electrode (GCE) using square wave voltammetry (SWV). After the optimization of experimental parameters, the limits of detection (at 3 σ) obtained for all aldehyde-2,4-DNPH were varied from 15.82 to 78.39 μmol L−1 and relative standard deviations were between 1.8 and 4.5%. Finally, the proposed method was applied to determine the aldehydes concentration in drinking water and orange juice samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Studies in environmentally controlled rooms have been used over the years to assess the impact of environmental tobacco smoke on indoor air quality. As new tobacco products are developed, it is important to determine their impact on air quality when used indoors. Before such an assessment can take place it is essential that the analytical methods used to assess indoor air quality are validated and shown to be fit for their intended purpose. Consequently, for this assessment, an environmentally controlled room was built and seven analytical methods, representing eighteen analytes, were validated. The validations were carried out with smoking machines using a matrix-based approach applying the accuracy profile procedure. The performances of the methods were compared for all three matrices under investigation: background air samples, the environmental aerosol of Tobacco Heating System THS 2.2, a heat-not-burn tobacco product developed by Philip Morris International, and the environmental tobacco smoke of a cigarette. The environmental aerosol generated by the THS 2.2 device did not have any appreciable impact on the performances of the methods. The comparison between the background and THS 2.2 environmental aerosol samples generated by smoking machines showed that only five compounds were higher when THS 2.2 was used in the environmentally controlled room. Regarding environmental tobacco smoke from cigarettes, the yields of all analytes were clearly above those obtained with the other two air sample types. Graphical abstractfx1Highlights· Selected indoor air quality methods were validated using accuracy profiles. · The impact of a novel Tobacco Heating System on these methods was assessed. · Environmental tobacco smoke and background air samples were also validated. · The methods were apt for the detection and quantification of 18 constituents in air. · Methods were applied for evaluating the impact of tobacco products on indoor air. Abbreviations [ABSTRACT FROM AUTHOR]

Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography–Diode Array Detector (HPLC–DAD) and Gas Chromatography–Selective Ion Monitoring–Mass Spectrometry (GC–SIM–MS). Analysis of DNPH cartridges by GC–SIM–MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p -tolualdehyde, m,o -molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6700 and 2300 μg kWh −1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3870 μg kWh −1 in HFO operation to 1540 μg kWh −1 in DF operation, which is 4–30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%). [ABSTRACT FROM AUTHOR]

In 2010 the European Commission placed a limit on the amount of free formaldehyde in carrageenan and processedEucheumaseaweed (PES) of 5 mg kg−1. Formaldehyde is not used in carrageenan and PES processing and accordingly one would not expect free formaldehyde to be present in carrageenan and PES. However, surprisingly high levels up to 10 mg kg−1have been found using the generally accepted AOAC and Hach tests. These findings are, per proposed reaction pathways, likely due to the formation of formaldehyde when sulphated galactose, the backbone of carrageenan, is hydrolysed with the strong acid used in these conventional tests. In order to minimise the risk of false-positives, which may lead to regulatory non-compliance, a new high-performance liquid chromatography (HPLC) method has been developed. Initially, carrageenan or PES is extracted with 2-propanol and subsequently reacted with 2,4-dinitrophenylhydrazine (DNPH) to form the chromophore formaldehyde-DNPH, which is finally quantified by reversed-phase HPLC with ultraviolet light detection at 355 nm. This method has been found to have a limit of detection of 0.05 mg kg−1and a limit of quantification of 0.2 mg kg−1. Recoveries from samples spiked with known quantities of formaldehyde were 95–107%. Using this more specific technique, 20 samples of carrageenan and PES were tested for formaldehyde. Only one sample had a detectable content of formaldehyde (0.40 mg kg−1), thus demonstrating that the formaldehyde content of commercial carrageenan and PES products are well below the European Commission maximum limit of 5 mg kg−1. [ABSTRACT FROM AUTHOR]

Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6050 and 2300 µg MJ-1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3500 µg MJ-1 in HFO operation to 1540 µg MJ-1 in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%). [ABSTRACT FROM AUTHOR]

This study concerns the development and validation of a complete method for the analysis of two highly reactive α-dicarbonyl compounds, glyoxal (Gly) and methylglyoxal (Mgly), in atmospheric fine particulate matter (PM). Method development included optimization of sample preparation procedures, e.g., filter extraction, concentration of extracts, derivatization and solid-phase extraction (SPE) of derivatives, as well as reversed-phase liquid chromatography coupled to electrospray ion-trap mass spectrometry (HPLC-ESI-IT/MS/MS) measurement parameters. Selectivity of detection was enhanced using tandem mass spectrometric analysis in ESI positive ion mode via two multiple reaction monitoring channels, m/ z 433 → m/ z 250 and m/ z 419 → m/ z 236 for Mgly and Gly. Retention times were 9.5 and 12.5 min for Gly- and Mgly-bis-hydrazone derivatives. Calibration ranged from 0.5 to 50 ng/mL. Inter-batch precision, expressed as relative standard deviation, was <15%. The method was shown to be unaffected by the sample matrix and to have recoveries of 100% and 60% for Gly and Mgly, respectively. Improved instrumental detection limits of 0.51 and 0.62 ng/mL for Gly and Mgly were achieved using a SPE method for the purification of 2,4-dinitrophenylhydrazine derivatization reagent solutions. This permitted the method to be used for analysis of filter samples obtained during a field study at the Taunus Observatory (mount Kleiner Feldberg, Germany). PM concentrations ranged from 0.81 to 1.18 ng/m for Gly and from 0.83 to 1.92 ng/m for Mgly. PM concentrations correlated to the concentration of NO with coefficients ( R) of 0.67 (Gly) and 0.78 (Mgly). [ABSTRACT FROM AUTHOR]

Abstract: Protein oxidation (P-OX) is an innovative topic of increasing interest among meat researchers. Carbonylation is generally recognized as one of the most remarkable chemical modifications in oxidized proteins. In fact, the quantification of protein carbonyls by the dinitrophenylhydrazine (DNPH) method is the most common procedure for assessing P-OX in meat systems. Numerous studies have investigated the occurrence of protein carbonylation right after slaughter and during subsequent processing and cold storage of meat. However, the significance of protein carbonylation in meat systems is still poorly understood. Beyond their role as markers of protein oxidation, specific protein carbonyls such as α-aminoadipic and γ-glutamic semialdehydes (AAS and GGS, respectively) are active compounds that may be implicated in several chemical reactions with relevant consequences on meat quality. The formation of protein carbonyls from particular amino acid side chains contribute to impair the conformation of myofibrillar proteins leading to denaturation and loss of functionality. Recent studies also highlight the potential impact of specific protein carbonyls in particular meat quality traits such as water-holding capacity (WHC), texture, flavor and its nutritional value. As a truly emerging topic, the results from current studies provide grounds from the development of further investigations. The present paper reviews the current knowledge on the mechanisms and consequences of protein carbonylation in meat systems and aims to encourage meat researchers to accomplish further investigations on this fascinating research topic. [Copyright &y& Elsevier]

In this work, the experimental compatibility between the standard DNPH-HPLC method and the gas chromatographic (GC) method (without any derivatization) was investigated for the analysis of atmospheric carbonyls. In the latter case, GC analysis was made based on adsorptive enrichment on solid sorbents followed by thermal desorption. For a comparative analysis between the two methods, we quantified the concentration levels of acetaldehyde from gaseous combustion samples of different charcoal products. The acetaldehyde concentration data, measured by the HPLC method (643 ± 1,689 ppb), were approximately 10% lower than the GC-based method (722 ± 1,788 ppb). As such, the differences in the measured concentrations were statistically insignificant. Although the percentage difference of the two methods fell within a relatively wide range, the results obtained by the GC-based method were comparable to those of the HPLC method with significantly strong correlations. The GC-based method, if tested for certain carbonyl species such as acetaldehyde, appeared to be a suitable alternative for the HPLC method. [ABSTRACT FROM AUTHOR]

Subjecting selected peptides to in vitro analyses covering their ability to interfere with the lipid oxidation chain reaction as well as to protect proteins from direct and indirect oxidation has provided the basis for a more detailed understanding of peptide-mediated protection in biological systems. The efficiency of peptides as radical scavengers and chain-breaking antioxidants in oxidizing lipid membranes was found to be low. Previous studies on antioxidative activity of peptides tend not to include comparisons with efficiencies of more well-documented antioxidants and/or use irrelevantly high dosages of peptides. The present study demonstrates that the effect of the investigated peptides towards oxidation in biological membrane systems is mainly a protection of vital proteins from being oxidatively modified. This protection is obtained through a prevention of lipid oxidation derived carbonylation (indirect protein oxidation) and through interference with aqueous radical species (direct protein oxidation), and it is only achieved if the peptides are present in high concentrations as sacrificial antioxidants. [ABSTRACT FROM AUTHOR]

Abstract: Liquid chromatography–electrospray ionisation–mass spectrometry (LC–ESI–MS) was applied as an advanced methodology to study the suitability of using α-aminoadipic semialdehyde (AAS) and γ-glutamic semialdehyde (GGS) as protein oxidation markers in meat products. The results obtained were compared to those obtained by using the DNPH-method and fluorescence spectroscopy for the analysis of protein carbonyls. Lipid oxidation was also investigated in order to elucidate the relationship between lipid and protein oxidation measurements. Both semialdehydes were originally detected in a food system which proves that lysine, arginine and proline are degraded as a result of oxidative reactions to yield AAS and GGS in meat products. A lack of consistency was observed between the MS results for AAS and GGS and the values obtained by the DNPH-method and the fluorescence spectroscopy. Unlike the last two methods, AAS and GGS measurements have proved to be unaffected by the composition or the structure of the food matrix providing precise information about the fate of particular amino acids during processing of muscle foods. These semialdehydes, and particularly GGS, could be used as indicators of protein oxidation in meat products like TBARS numbers are commonly used as lipid oxidation markers. In fact, a significant correlation was found between GGS values and TBARS highlighting the timely interaction between lipid and protein oxidation. [Copyright &y& Elsevier]

Abstract: Formose sugar and formaldehyde (HCHO) were analyzed using high-performance liquid chromatography (HPLC) utilizing a CarboPac PA1 column (Dionex) and pulsed amperometric detection. This HPLC system was unsuitable for the analysis of formose sugar and HCHO and thus reducing sugars and unconverted HCHO were determined by endowing them with charges through a derivatization method using 2,4-dinitrophenylhydrazine. The separation and detection of compounds were performed by three Chromolith RP-C18 columns (Merck) and diode array detection, at a wavelength of 360nm ultraviolet light, respectively. Lower sugars (except HCHO) showed some instabilities when the derivatized samples were kept for the extended periods of time. For C5 and consecutive higher sugars, a certain derivatization time was necessary. In the present case (formose reaction with partial HCHO conversion), approximately 18h may be a reasonable compromise for the derivatization reaction. A derivatization agent to compound mole ratio of up to 100:1 was required to complete the derivatization of C4 and higher sugars. However, the analysis of C4 and consecutive higher sugars is problematic for example due to overlapping of peaks or branched-chain sugars. [Copyright &y& Elsevier]

Three simple, rapid, and sensitive ion-selective electrodes for indirect determination of free formaldehyde in urea glue and wastewater have been developed. The methods are based on the formation of the membrane sensors 2,4-dinitrophenylhydrazine-phosphtungestic acid (DNPH-PTA), 2,4-dinitrophenylhydrazine-phosphomolybdic acid (DNPH-PMA), and 2,4-dinitrophenylhydrazine-tetraphenylborate (DNPH-TPB) as neutral carriers. The sensors are stable and show fast potential responses of 30 s, and near-Nernstian cationic slopes of 56.2 ± 0.5, 54.3 ± 0.5, and 53.8 ± 0.4 mV per decade of activity between pH 0.5 and 3.5 over a wide range of 2,4-dinitrophenylhydrazine concentrations (1 × 10-5 to 1 × 10-2 M). These sensors were used for indirect determination of formaldehyde over concentration range (1 × 10-4 to 1 × 10-1 M). The selectivity coefficients of the developed sensors indicate excellent selectivity for 2,4 DNPH over a large number of organic and inorganic species. The mediator o-nitrophenyloctyl ether has a significant affect on the lifetime of the fabricated sensors. The analytical applications of the proposed sensors showed good results for indirect determination of formaldehyde in formaldehyde solutions, wastewater solutions, and free formaldehyde in urea-formaldehyde liquid and powder glues. The results were compared favourably with that obtained by ASTM, colorimetric, and British Standard methods. [ABSTRACT FROM AUTHOR]

Abstract: Formaldehyde concentrations have been measured in the university libraries in Strasbourg (east of France). Infrared diode laser spectroscopy and a conventional DNPH-derivatization method followed by liquid chromatography coupled to UV detection have been used simultaneously for comparison purposes. The formaldehyde concentrations obtained by both the techniques were always in excellent agreement, showing that the infrared diode laser spectroscopy can be used for formaldehyde monitoring in indoor atmosphere, with a time resolution of few minutes. Formaldehyde concentrations were generally found to be in the range 8–33μgm−3, except for two libraries where concentrations of 82 and 105μgm−3 have been measured. Using the results obtained by both techniques, the resulting mean formaldehyde level in the investigated libraries was then 33.5±31.2μgm−3, where the quoted error correspond to the standard deviation. Acetaldehyde and hexanal levels have also been quantified by duplicated measurements in the same libraries by the DNHP-derivatization method. They ranged from 0.0 to 11.3μgm−3 for acetaldehyde and from 1.0 to 16.7μgm−3 for hexanal and their mean values were found to be 2.1±3.2μgm−3 (acetaldehyde) and 4.0±4.4μgm−3 (hexanal), where the quoted errors correspond to the standard deviation. [Copyright &y& Elsevier]

Abstract: Uric acid is the end product of purine metabolism in humans. It has been pointed out that uric acid acts as an antioxidant and is capable to react with biologically relevant oxidants to form allantoin. Therefore, measurement of allantoin in humans was proposed as a marker of oxidative stress. We estimated allantoin in human plasma obtained from the patients with chronic renal failure before hemodialysis (n =30), patients with non-insulin dependent diabetes mellitus (n =30) and blood donors (n =30) using a method based on selective isolation of allantoin from deproteinized plasma samples on AG 1-X8 resin and its derivatization to glyoxylate-2,4-dinitrophenylhydrazone. The method is free from urate and glyoxylate interferences. Separation of glyoxylate-2,4-dinitrophenylhydrazone from other hydrazones was achieved on reversed phase HPLC with gradient elution and UV/VIS detection at 360 nm. The analytical performance of this method is satisfactory with intra-assay CV 5.7%, inter-assay CV 8.3% and recovery 94.1%. We have determined other parameters of oxidative stress (malondialdehyde, total antioxidant status, superoxide dismutase and glutathione peroxidase) too. The preliminary reference range of allantoin in a group of blood donors is 4.76±2.99 μmol/L. In the patients with chronic renal failure and the patients with non-insulin dependent diabetes mellitus we found allantoin levels in plasma (27.1±13.8) μmol/L and (11.08±5.90) μmol/L, respectively. It seems that allantoin is a possible indicator of free radical damage in vivo. [Copyright &y& Elsevier]

An automated monitoring system for various C 1 to C 5 gas-phase organic carbonyls in ambient air is described. The system consists of a parallel plate diffusion scrubber (PPDS), which is coupled with a high-performance liquid chromatography-ultraviolet (HPLC-UV) system using an automated injection valve. Compared with an annular diffusion scrubber (DS) employed so far for gas-phase carbonyl monitoring, PPDS shows an improved collection efficiency for formaldehyde, acetaldehyde, propionaldehyde, and acetone with >97% at an airflow rate of 0.5 L/min. High gas-liquid concentration ratios of PPDS and an optimised HPLC-UV system allow limits of detection (LOD) in a range of 80-500 pptv. A low liquid hold-up volume of the PPDS results in a short response time of about 10 min. Additionally, the optimised analysis time for 13 carbonyl compounds containing calibration standard enables brief measurement intervals of 25 min. The developed PPDS-HPLC system shows its reliability from urban site monitoring in Seoul, South Korea. [ABSTRACT FROM AUTHOR]

Formaldehyde, acetaldehyde, acetone, ozone and nitrogen dioxide were measured in ambient air after having simultaneously collected them on a pair of silica gel cartridges coated with 2,4-dinitro-phenylhydrazine (DNPH) and 1-methyl-1-(2,4-dinitro)-phenylhydrazine (MDNPH), respectively. By reaction with DNPH, the three carbonyls were derivatized to hydrazones and NO2 converted into 2,4-dinitrophenylazide (DNPA), whilst both NO2 and O3 produced N-methyl-2,4-dinitroaniline (MDNA) on MDNPH coating, which was also able to fast react with formaldehyde. The different derivatives were then separated, identified and quantified by HPLC-UV and HRGC-MS. The limits of detection (LOD) for Ox (O3+NO2), NO2, HCHO, CH3CHO and CH3COCH3 were 1.5, 0.4, 0.7, 0.7 and 0.7 ppbv, respectively, for 30 l (1 h) air sampled. When compared with ozone photometric and nitrogen dioxide chemiluminescent analysers, the proposed chromatographic methods, especially HPLC, demonstrated good accuracy (14% for Ox in the 20–100 ppbv range and 21% for NO2 in the 3–14 ppbv range) under field sampling conditions. The comparison between DNPH and MDNPH cartridges about lower carbonyls showed that only HCHO was efficiently collected on MDNPH cartridges, whilst CH3CHO and CH3COCH3 were partly and almost completely lost, respectively. However, significant differences in HCHO mixing ratios (39% on average) were observed with the two types of cartridges. [Copyright &y& Elsevier]

The present paper describes a procedure that formaldehyde in air was preconcentrated in a membrane cell and its content was determined by adsorptive polarography. First the formaldehyde in air samples was preconcentrated in a membrane cell using water, then the formaldehyde reacted with 2,4-dinitrophenyl hydrazine to form 2,4-dinitrophenyl hydrazone, which can be adsorbed at the mercury electrode and yields a sensitive adsorptive polarographic wave. Over the range 6.0×10−10–5.0×10−6 M, the peak currents are linearly proportional to the concentration of formaldehyde, the detection limit is 2.0×10−10 M. [Copyright &y& Elsevier]

Electronic cigarette (e-cigarette) market increased by 122% during 2014-2020 and is expected to continue growing rapidly. Despite their popularity, e-cigarettes are known to emit dangerous levels of toxic compounds (e.g., carbonyls), but a lack of accurate and efficient testing methods is hindering the characterization of e-cigarette aerosols emitted by a wide variety of e-cigarette devices, e-liquids, and use patterns. The aim of this study is to fill this gap by developing an automated E-cigarette Aerosol Collection and Extraction System (E-ACES) consisting of a vaping machine and a collection/extraction system. The puffing system was designed to mimic e-cigarette use patterns (i.e., power output and puff topography) by means of a variable power-supply and a flow control system. The sampling system collects e-cigarette aerosols using a combination of glass wool and a continuously wetted denuder. After the collection stage, the system is automatically washed with absorbing and extracting liquids (e.g., methanol, an acetaldehyde-DNPH solution). The entire system is controlled by a computer. E-ACES performance was evaluated against conventional methods during measurements of nicotine and carbonyl emissions from a tank type e-cigarette. Nicotine levels measured using glass fiber filters and E-ACES were not significantly different: 201.2 ± 6.2 and 212.5 ± 17 μg/puff ( p = 0.377), respectively. Differences in formaldehyde and acetaldehyde levels between filter-DNPH cartridges and the E-ACES were 14% ( p = 0.057) and 13% ( p = 0.380), respectively. The E-ACES showed reproducible nicotine and carbonyl testing results for the selected e-cigarette vaping conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Son and Khlystov.)

2,4-Dinitrophynylhydrazine and two thiocyanate ions in a (M:L1:L2) 1:2:2 molar ratio was synthesized in the complexes of Co(II) and Ni(II). The prepared compounds were identified through a C.H.N.S. analysis, conductivity measurements, powder X-ray diffraction (PXRD), the infrared spectrum, and a UV-visible spectrum analysis, in addition to the magnetic properties being measured. The measurements of the molar conductance implieda nonelectrolytic nature of compounds Co(II) and Ni(II). The magnetic susceptibility, as well as electronic spectra, represented all the metal complexesthroughoctahedral geometry, respectively. The PXRD patterns suggested that all the complexes were an orthorhombic system with unit cell parameters. The in-vitro biological activity of the ligand and the metal complexes were screened against the Gram-positive and negative pathogenic bacteria Staphylococcus aureus, Bacillus subtilis, Pseudomonas, aeruginosa and Escherichia coli, as well as the fungal species of Aspergillusniger and Candida albicans.Thus, the metal complexes showeda high efficiency of antimicrobial activity compared with the ligand. Furthermore, applications of the ligand, as well as the metal complexes, were tested for in-vitro antioxidant potential in aDPPH assay. The results showed that the activity of the metal complexes with the in-vitro antioxidant was more active than that of 2,4-dinitrophenylhydrazine(DNPH). [ABSTRACT FROM AUTHOR]

Airborne aldehydes have a significant impact on human health, especially in confined spaces such as tunnels, vehicle depots, industrial and construction sites where combustion devices are in operation. The standard method for the measurement of aldehydes (formaldehyde and acetaldehyde) uses the 2,4-dinitrophenylhydrazine (DNPH) derivatisation method. However this method has been reported to be prone to interference from ozone and NO 2. The interference from these compounds have been viewed as chromatographic interferences on the quantification of formaldehyde. However, in these polluted environments, elevated levels of NO 2 along with NO and CO are normally present. This study quantifies the impact these gases have on the quantification of formaldehyde and acetaldehyde, by evaluating the chromatographic interferences, consumption of the DNPH during sampling, and the effect these gases have on the capture and retention of the aldehydes on the DNPH cartridge during sampling. For the first time, CO was shown to react with DNPH and interfere with the determination of acetone. The reaction product of CO with DNPH was determined to be a compound that could be mistaken for acetone-DNPH. It has been found that the presence of NO, NO 2 and CO in the sampled air consumes the DNPH cartridges, which results in the loss of formaldehyde and acetaldehyde during long-term sampling, and therefore extra capacity of DNPH is required for the measurement of formaldehyde and acetaldehyde in polluted environments. These findings reveal a potential risk of underestimation of formaldehyde and acetaldehyde measurements in a polluted workspaces such as a diesel engine operated environment where NO x and CO concentration levels could be high. • CO reacts with DNPH to form a product that can be mistaken for acetone-DNPH. • NO x and CO gases interfere with the adsorption of aldehydes onto the DNPH cartridge. • Nitrogen dioxide and carbon monoxide reduce the capacity of a DNPH cartridge. • Required amount of DNPH on the cartridge must also take into account the concentration of CO and NO 2. [ABSTRACT FROM AUTHOR]