Study on the thermal oxidation of oleic, linoleic and linolenic acids by synchrotron radiation photoionization mass spectrometry.

RATIONALE: Cooking oil fumes contain numerous hazardous and carcinogenic chemicals, posing potential threats to human health. However, the sources of these species remain ambiguous, impeding health risk assessment, pollution control and mechanism research. METHODS: To address this issue, the thermal oxidation of three common unsaturated fatty acids (UFAs), namely oleic, linoleic and linolenic acids, present in vegetable oils was investigated. The volatile and semi-volatile products were comprehensively characterized by online synchrotron radiation photoionization mass spectrometry (SR-PIMS) with two modes, which were validated and complemented using offline gas chromatography (GC)/MS methods. Tunable SR-PIMS combined with photoionization efficiency curve simulation enabled the recognition of isomers/isobars in gaseous fumes. RESULTS: SR-PIMS revealed over 100 products, including aldehydes, alkenes, furans, aromatic hydrocarbons, etc., such as small molecules of formaldehyde, acetaldehyde, acrolein, ethylene and furan, which are not readily detected by conventional GC/MS; and some unreported fractions, e.g. ketene, 4-ethylcyclohexene and cycloundecene(E), were also observed. Furthermore, real-time monitoring of product emissions during the thermal oxidation of the three UFAs via SR-PIMS revealed that linolenic acid may be the major source of acrolein. CONCLUSION: SR-PIMS has been demonstrated as a powerful technique for online investigation of cooking oil fumes. This study achieved comprehensive characterization of volatile and semi-volatile products from the thermal oxidation of oleic, linoleic and linolenic acids, facilitating the traceability of species in cooking fumes and aiding in exploring the thermal reactions of different vegetable oils.

Real-world emission characteristics of carbonyl compounds from agricultural machines based on a portable emission measurement system.

Emissions of carbonyl compounds from agricultural machines cannot be ignored. Carbonyl compounds can cause the formation of ozone (O3) and secondary organic aerosols, which can cause photochemical smog to form. In this study, 20 agricultural machines were tested using portable emission measurement system (PEMS) under real-world tillage processes. The exhaust gases were sampled using 2,4-dinitrophenylhydrazine cartridges, and 15 carbonyl compounds were analyzed by high-performance liquid chromatography. Carbonyl compound emission factors for agricultural machines were 51.14-3315.62 mg/(kg-fuel), and were 2.58 ± 2.05, 0.86 ± 1.07 and 0.29 ± 0.20 g/(kg-fuel) for China 0, China II and China III emission standards, respectively. Carbonyl compound emission factor for sowing seeds of China 0 agricultural machines was 3.32 ± 1.73 g/(kg-fuel). Formaldehyde, acetaldehyde and acrolein were the dominant carbonyl compounds emitted. Differences in emission standards and tillage processes impact ozone formation potential (OFP). The mean OFP was 20.15 ± 16.15 g O3/(kg-fuel) for the China 0 emission standard. The OFP values decreased by 66.9% from China 0 to China II, and 67.4% from China II to China III. The mean OFP for sowing seeds of China 0 agricultural machines was 25.92 ± 13.84 g O3/(kg-fuel). Between 1.75 and 24.22 times more ozone was found to be formed during sowing seeds than during other processes for China 0 and China II agricultural machines. Total carbonyl compound emissions from agricultural machines in China was 19.23 Gg in 2019. The results improve our understanding of carbonyl compound emissions from agricultural machines in China.

Chemical analysis of fresh and aged Australian e-cigarette liquids.

OBJECTIVES: To assess the chemical composition of electronic cigarette liquids (e-liquids) sold in Australia, in both their fresh and aged forms. DESIGN, SETTING: Gas chromatography-mass spectrometry analysis of commercial e-liquids sold in Australia (online and physical stores). MAIN OUTCOME MEASURES: Chemical composition of 65 Australian e-liquids - excipients/solvents, flavouring chemicals, other known e-liquid constituents (including nicotine), and polycyclic aromatic hydrocarbons - before and after an accelerated ageing process that simulated the effects of vaping. RESULTS: The measured levels of propylene glycol and glycerol often diverged from those recorded on the e-liquid label. All e-liquids contained one or more potentially harmful chemicals, including benzaldehyde, menthol, trans-cinnamaldehyde, and polycyclic aromatic hydrocarbons. Nicotine or nicotyrine were detected in a small proportion of e-liquids at extremely low concentrations. CONCLUSIONS: Australian e-liquids contain a wide variety of chemicals for which information on inhalation toxicity is not available. Further analyses are required to assess the potential long term effects of e-cigarette use on health.

Composition of aerosols from thermal degradation of flavors used in ENDS and tobacco products.

Aim: The cardiovascular toxicity of unheated and heated flavorants and their products as commonly present in electronic cigarette liquids (e-liquids) was evaluated previously in vitro. Based on the results of in vitro assays, cinnamaldehyde, eugenol, menthol, and vanillin were selected to conduct a detailed chemical analysis of the aerosol generated following heating of each compound both at 250 and 750 °C. Materials and Methods: Each flavoring was heated in a drop-tube furnace within a quartz tube. The combustion atmosphere was captured using different methods to enable analysis of 308 formed compounds. Volatile organic compounds (VOCs) were captured with an evacuated Summa canister and assayed via gas chromatography interfaced with mass spectrometry (GC-MS). Carbonyls (aldehydes and ketones) were captured using a 2,4-dinitrophenylhydrazine (DNPH) cartridge and assayed via a high-performance liquid chromatography-ultra-violet (HPLC-UV) assay. Polyaromatic hydrocarbons (PAHs) were captured using an XAD cartridge and filter, and extracts were assayed using GC-MS/MS. Polar compounds were assayed after derivatization of the XAD/filter extracts and analyzed via GC-MS. Conclusion: At higher temperature, both cinnamaldehyde and menthol combustion significantly increased formaldehyde and acetaldehyde levels. At higher temperature, cinnamaldehyde, eugenol, and menthol resulted in increased benzene concentrations. At low temperature, all four compounds led to higher levels of benzoic acid. These data show that products of thermal degradation of common flavorant compounds vary by flavorant and by temperature and include a wide variety of harmful and potentially harmful constituents (HPHCs).

Simultaneous Estimation of Cinnamaldehyde and Eugenol in Essential Oils and Traditional and Ultrasound-Assisted Extracts of Different Species of Cinnamon Using a Sustainable/Green HPTLC Technique.

A wide range of analytical techniques are reported for the determination of cinnamaldehyde (CCHO) and eugenol (EOH) in plant extracts and herbal formulations either alone or in combination. Nevertheless, sustainable/green analytical techniques for the estimation of CCHO and EOH either alone or in combination are scarce in the literature. Accordingly, the present research was carried out to establish a rapid, highly sensitive, and sustainable high-performance thin-layer chromatography (HPTLC) technique for the simultaneous estimation of CCHO and EOH in the traditional and ultrasound-assisted methanolic extracts of Cinnamomum zeylanicum,C. burmannii, and C. cassia and their essential oils. The simultaneous estimation of CCHO and EOH was performed through NP-18 silica gel 60 F254S HPTLC plates. The cyclohexane/ethyl acetate (90:10, v v-1) solvent system was optimized as the mobile phase for the simultaneous estimation of CCHO and EOH. The greenness score of the HPTLC technique was predicted using AGREE software. The entire analysis was carried out at a detection wavelength of 296 nm for CCHO and EOH. The sustainable HPTLC technique was observed as linear in the range 10-2000 ng band-1 for CCHO and EOH. The proposed technique was found to be highly sensitive, rapid, accurate, precise, and robust for the simultaneous estimation of CCHO and EOH. The content of CCHO in traditional methanolic extracts of C. zeylanicum,C. burmannii, and C. cassia was found to be 96.36, 118.49, and 114.18 mg g-1, respectively. However, the content of CCHO in ultrasound-assisted methanolic extracts of C. zeylanicum,C. burmannii, and C. cassia was found to be 111.57, 134.39, and 129.07 mg g-1, respectively. The content of CCHO in essential oils of C. zeylanicum,C. burmannii, and C. cassia was found to be 191.20, 214.24, and 202.09 mg g-1, respectively. The content of EOH in traditional methanolic extracts of C. zeylanicum,C. burmannii, and C. cassia was found to be 73.38, 165.41, and 109.10 mg g-1, respectively. However, the content of EOH in ultrasound-assisted methanolic extracts of C. zeylanicum,C. burmannii, and C. cassia was found to be 87.20, 218.09, and 121.85 mg g-1, respectively. The content of EOH in essential oils of C. zeylanicum,C. burmannii, and C. cassia was found to be 61.26, 79.21, and 69.02 mg g-1, respectively. The amounts of CCHO and EOH were found to be significantly higher in ultrasound-assisted extracts of all species compared to its traditional extraction and hence ultrasound extraction has been proposed as a superior technique for the extraction of CCHO and EOH. The AGREE analytical score of the present analytical technique was predicted as 0.75, suggesting excellent greenness profile of the proposed analytical technique. Based on all these observations and results, the proposed sustainable HPTLC technique can be successfully used for the simultaneous estimation of CCHO and EOH in different plant extracts and herbal products.

Quantitative Liquid Chromatography-Nanoelectrospray Ionization-High-Resolution Tandem Mass Spectrometry Analysis of Acrolein-DNA Adducts and Etheno-DNA Adducts in Oral Cells from Cigarette Smokers and Nonsmokers.

Cigarette smoking is an important source of human exposure to toxicants and carcinogens and contributes significantly to cancer morbidity and mortality worldwide. Acrolein, a widespread environmental pollutant, is present in relatively high amounts in cigarette smoke and can react directly with DNA to form DNA adducts, which serve as important biomarkers for the assessment of exposure to acrolein and its potential role in smoking related cancer. Etheno-DNA adducts are promutagenic DNA lesions that can derive from exogenous chemicals as well as endogenous sources, including lipid peroxidation. In this study, we developed a combined method for the quantitation of (6R/S)-3-(2'-deoxyribos-1'-yl)-5,6,7,8,-tetrahydro-6-hydroxypyrimido[1,2-a]purine-10(3H)-one (α-OH-Acr-dGuo), (8R/S)-3-(2'-deoxyribos-1'-yl)-5,6,7,8,-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10(3H)-one (γ-OH-Acr-dGuo), 1,N6-etheno-dAdo (εdAdo), and 3,N4-etheno-dCyd (εdCyd) adducts in oral rinse and cytobrush DNA from smokers and nonsmokers by liquid chromatography-nanoelelctrospray ionization-high-resolution tandem mass spectrometry (LC-NSI-HRMS/MS). For oral rinse samples, there was a statistically significant difference between the levels of α-OH-Acr-dGuo, γ-OH-Acr-dGuo, εdAdo, and εdCyd in smokers (12.1 ± 17.9, 163 ± 227, 182 ± 568, and 194 ± 400 adducts/109 nucleotides, respectively) and nonsmokers (1.85 ± 2.08, 5.95 ± 4.23, 7.69 ± 11.7, and 6.07 ± 10.9 adducts/109 nucleotides, respectively). For cytobrush samples, there was a statistically significant difference between the levels of γ-OH-Acr-dGuo and εdAdo in smokers (259 ± 540 and 82.9 ± 271 adducts/109 nucleotides, respectively) and nonsmokers (7.37 ± 5.09 and 16.2 ± 30.2 adducts/109 nucleotides, respectively) but not for α-OH-Acr-dGuo and εdCyd. Our results demonstrate that oral mucosa cells are an excellent source of material for evaluating DNA adducts to be used as biomarkers of tobacco smoke exposure and molecular changes potentially related to cancer.

Selected Harmful and Potentially Harmful Constituents Levels in Commercial e-Cigarettes.

A broad range of commercially available electronic cigarette (e-cigarette) systems were tested for levels of emissions of harmful and potentially harmful constituents (HPHC), with a particular focus on the carbonyls: acetaldehyde, acrolein, and formaldehyde. The tobacco-specific nitrosamines N'-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-bipyridyl)-1-butanone; the elements arsenic, cadmium, chromium, lead, and nickel; benzene; 1,3-butadiene; and benzo(a)pyrene were also quantified. The results show that except for the levels of carbonyls, all types of e-cigarettes performed in a similar manner, and emission levels for HPHCs were generally not quantifiable. However, levels of carbonyls, especially formaldehyde, were highly variable. Overall, the lowest levels of formaldehyde were observed in cartridge systems, which generally achieved substantial reductions in yields in comparison with cigarette smoke. Formaldehyde levels in open tank systems were variable; however, the median formaldehyde levels across different brands were substantially lower than the formaldehyde levels in cigarette smoke. The results for variable-power devices operated at the highest voltage confirmed existing literature data regardless of orientation and differences in puffing regimes. Furthermore, our results show that many products deliver consistent HPHC yields over a broad range of testing conditions (with minimal variability from one device to another, under a range of puffing conditions). However, some products exhibit high variability in emissions of HPHCs. The use of air blanks is further highlighted to assess nonproduct-related contributions to HPHC levels to avoid misrepresentation of the data. Overall, our results highlight that some but not all electronic cigarettes deliver low levels of carbonyls consistently across the full e-liquid depletion cycle under different test conditions. The need for further research and standardization work on assessment of variable-voltage electronic cigarettes is emphasized.

Disease-associated acrolein: A possible diagnostic and therapeutic substrate for in vivo synthetic chemistry.

Acrolein, a highly reactive α,ß-unsaturated aldehyde, is a compound to which humans are exposed in many different situations and often causes various human diseases. This paper summarizes the reports over the past twenty-five years regarding disease-associated acrolein detected in clinical patients and the role acrolein plays in various diseases. In several diseases, it was found that the increased acrolein acts as a pathogenetic factor. Thus, we propose the utility of over-produced acrolein as a substrate for a promising therapeutic or diagnostic method applicable to a wide range of diseases based on an in vivo synthetic chemistry strategy.

Metabolomic profiling and comparison of major cinnamon species using UHPLC-HRMS.

The metabolomic profiles of four major species of cinnamon (Cinnamomum verum, C. burmannii, C. loureiroi, and C. cassia) were investigated by ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Thirty-six metabolites were tentatively characterized, belonging to various compound groups such as phenolic glycosides, flavan-3-ols, phenolic acids, terpenes, alkaloids, and aldehydes. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) on the HRMS data matrix resulted in a clear separation of the four cinnamon species. Coumarin, cinnamaldehyde, methoxycinnamaldehyde, cinnamoyl-methoxyphenyl acetate, proanthocyanidins, and other components varied among the four species. Such variations were used to develop a step-by-step strategy for differentiating the four cinnamon species based on their levels of pre-selected components. This study suggests a significant variation in the phytochemical compositions of different cinnamon species, which have a direct influence on cinnamon's health benefit potentials. Graphical Abstract.

Emissions of Free Radicals, Carbonyls, and Nicotine from the NIDA Standardized Research Electronic Cigarette and Comparison to Similar Commercial Devices.

E-cigarettes (e-cigs) are a diverse and continuously evolving group of products with four generations currently in the market. The National Institute on Drug Abuse (NIDA) standardized research e-cigarette (SREC) is intended to provide researchers with a consistent e-cig device with known characteristics. Thus, we conducted laboratory-based characterizations of oxidants and nicotine in aerosols produced from SREC and other closed-system, breath-activated, commercially available e-cigs (Blu and Vuse). We hypothesized that oxidant and nicotine production will be significantly affected in all devices by changes in puffing parameters. All e-cigs were machine vaped and the aerosols generated were examined for nicotine, carbonyls, and free-radicals while varying the puff-volumes and puff-durations to reflect typical human usage. The data were normalized on a per puff, per gram aerosol, and per milligram nicotine basis. We found that aerosol production generally increased with increasing puff-duration and puff-volume in all e-cigs tested. Increased puff-duration and puff-volume increased nicotine delivery for Blu and Vuse but not the SREC. We report, for the first time, reactive free-radicals in aerosols from all closed-system e-cigs tested, albeit at levels lower than cigarette smoke. Formaldehyde, acetaldehyde, acetone, and propionaldehyde were detected in the aerosols of all tested e-cigs. Carbonyl and free radical production is affected by puff-duration and puff volume. Overall, SREC was more efficient at aerosol and nicotine production than both Blu and Vuse. In terms of carbonyl and free radical levels, SREC delivered lower or similar levels to both other devices.

Tetramethylrhodamine is an essential scaffold of azide probe in detecting cellular acrolein.

Tetramethylrhodamine (TAMRA)-phenyl azide is a chemical probe used to detect intracellular acrolein directly in live cells. Herein, we demonstrated that TAMRA is the optimum fluorophore for the probe. TAMRA-phenyl azide was used to reveal that high levels of acrolein are generated in a variety of breast cancer cells, regardless of the tumor subtype. These findings corroborate the analysis presented in our previous report, in which TAMRA-phenyl azide was used to label breast cancer tissues resected from breast cancer patients. Because high levels of acrolein were generated in all cancer cell types, we believe that acrolein detection may be useful as a general method for labeling cancerous tissues.

Isoprene photochemistry over the Amazon rainforest.

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.

Sources of methacrolein and methyl vinyl ketone and their contributions to methylglyoxal and formaldehyde at a receptor site in Pearl River Delta.

Methacrolein (MACR) and methyl vinyl ketone (MVK) are two major intermediate products from the photochemical oxidation of isoprene, the most important biogenic volatile organic compound. In addition, MACR and MVK have primary emissions. Investigating the sources and evolution of MACR and MVK could provide helpful information for the oxidative capacity of the atmosphere. In this study, hourly measurements of isoprene, MACR, and MVK were conducted at a receptor site in the Pearl River Delta region (PRD), i.e., the Heshan site (HS), from 22 October to 20 November, 2014. The average mixing ratios of isoprene, MACR and MVK were 151 ±â€¯17, 91 ±â€¯6 and 79 ±â€¯6 pptv, respectively. The daily variations and the ratios of MVK/MACR during daytime and nighttime suggested that other sources besides isoprene photooxidation influenced the MACR and MVK abundances at the HS. Positive matrix factorization was utilized to resolve the sources of MACR and MVK. Five sources were identified and quantified, including biogenic emissions, biomass burning, secondary formation, diesel, and gasoline vehicular emissions. Among them, secondary formation made the greatest contribution to observed MACR and MVK with average contributions of ~45% and ~70%, respectively. Through the yields of secondary products from the oxidation of MACR and MVK by the OH radical and the concentrations of MACR and MVK, it was found that methylglyoxal and formaldehyde were the main oxidation products of MACR and MVK at the HS site. Overall, this study evaluated the roles of primary emissions on ambient levels of MACR and MVK and advanced the understanding of photochemical oxidation of MACR and MVK in the PRD.

Compensatory Puffing With Lower Nicotine Concentration E-liquids Increases Carbonyl Exposure in E-cigarette Aerosols.

Introduction: Article 20 of the European Tobacco Products Directive (EU-TPD) specifies that e-liquids should not contain nicotine in excess of 20 mg/mL, thus many vapers may be compelled to switch to lower concentrations and in so doing, may engage in more intensive puffing. This study aimed to establish whether more intensive puffing produces higher levels of carbonyl compounds in e-cigarette aerosols. Methods: Using the HPLC-UV diode array method, four carbonyl compounds (formaldehyde, acetaldehyde, acetone, and acrolein) were measured in liquids and aerosols from nicotine solutions of 24 and 6 mg/mL. Aerosols were generated using a smoking machine configured to replicate puffing topography data previously obtained from 12 experienced e-cigarette users. Results: Carbonyl levels in aerosols from the puffing regimen of 6 mg/mL were significantly higher (p < .05 using independent samples t tests) compared with those of 24 mg/mL nicotine. For the 6 and 24 mg/mL nicotine aerosols respectively, means ± SD for formaldehyde levels were 3.41 ± 0.94, and 1.49 ± 0.30 µg per hour (µg/h) of e-cigarette use. Means ± SD for acetaldehyde levels were 2.17 ± 0.36 and 1.04 ± 0.13 µg/h. Means ± SD for acetone levels were 0.73 ± 0.20 and 0.28 ± 0.14 µg/h. Acrolein was not detected. Conclusions: Higher levels of carbonyls associated with more intensive puffing suggest that vapers switching to lower nicotine concentrations (either due to the EU-TPD implementation or personal choice), may increase their exposure to these compounds. Based on real human puffing topography data, this study suggests that limiting nicotine concentrations to 20 mg/mL may not result in the desired harm minimalization effect. Implications: More intensive puffing regimens associated with the use of low nicotine concentration e-liquids can lead to higher levels of carbonyl generation in the aerosol. Although in need of replication in a larger sample outside a laboratory, this study provides pragmatic empirical data on the potential risks of compensatory puffing behaviors in vapers, and can help to inform future regulatory decisions on nicotine e-liquid concentrations. The cap on nicotine concentration at 20 mg/mL set by the EU-TPD may therefore have the unintended consequence of encouraging use of lower nicotine concentration e-liquid, in turn increasing exposure to carbonyl compounds through compensatory puffing.

Acrolein Exposure in Hookah Smokers and Non-Smokers Exposed to Hookah Tobacco Secondhand Smoke: Implications for Regulating Hookah Tobacco Products.

Introduction: Acrolein is a highly ciliatoxic agent, a toxic respiratory irritant, a cardiotoxicant, and a possible carcinogen present in tobacco smoke including hookah tobacco. Methods: 105 hookah smokers and 103 non-smokers attended exclusively hookah smoking social events at either a hookah lounge or private home, and provided urine samples the morning of and the morning after the event. Samples were analyzed for 3-hydroxypropylmercapturic acid (3-HPMA), a metabolite of acrolein. Results: Geometric mean (GM) urinary 3-HPMA levels in hookah smokers and non-smokers exposed to secondhand smoke (SHS) increased significantly, 1.41 times, 95% CI = 1.15 to 1.74 and 1.39 times, 95% CI = 1.16 to 1.67, respectively, following a hookah social event. The highest increase (1.68 times, 95% CI = 1.15 to 2.45; p = 0.007) in 3-HPMA post a hookah social event was among daily hookah smokers (GM, from 1991 pmol/mg to 3348 pmol/mg). Pre-to-post event change in urinary 3-HPMA was significantly positively correlated with pre-to-post event change in urinary cotinine among hookah smokers at either location of hookah event, (ρ = 0.359, p = 0.001), and among non-smokers in hookah lounges (ρ = 0.369, p = 0.012). Conclusions: Hookah tobacco smoke is a source of acrolein exposure. Findings support regulating hookah tobacco products including reducing humectants and sugar additives, which are precursors of acrolein under certain pyrolysis conditions. We suggest posting health warning signs for indoor smoking in hookah lounges, and encouraging voluntary bans of smoking hookah tobacco in private homes. Implications: Our study is the first to quantify the increase in acrolein exposure in hookah smokers and non-smokers exposed to exclusively hookah tobacco SHS at hookah social events in homes or hookah lounges. Our findings provide additional support for regulating hookah tobacco product content, protecting non-smokers' health by posting health warning signs for indoor smoking in hookah lounges, and encouraging home bans on hookah tobacco smoking to safeguard vulnerable residents.

Volatiles from Cinnamomum cassia buds.

While the chemical composition of leaf and stem bark essential oils of the Chinese cinnamon, Cinnamomum cassia (L.) J. Presl, has been well investigated, little is known about the volatilom of its buds, which appeared recently on German markets. Soxhlet extracts of the commercial samples were prepared, fractionated using silica gel and characterised by gas chromatography-flame ionisation detector (GC-FID) for semi-quantification, by gas chromatography-mass spectrometry (GC-MS) for identification and by GC-FID/olfactometry for sensory evaluation. Cinnamaldehyde was the most abundant compound with concentrations up to 40 mg/g sample. In total, 36 compounds were identified and 30 were semi-quantified. The extracts contained mostly phenylpropanoids, mono- and sesquiterpene hydrocarbons and oxygenated derivatives. Because of the high abundance of cinnamaldehyde, the aldehyde fraction was removed from the extracts by adding hydrogen sulphite to improve both the detection of trace compounds and column chromatography. The aldehyde fraction was analysed by GC-MS separately. The highest flavour dilution factor of 316 was calculated for cinnamaldehyde. Other main sensory contributors were 2-phenylethanol and cinnamyl alcohol. This report provides the first GC-olfactometry data of a plant part of a Cinnamomum species. The strongly lignified C. cassia buds combine a high abundance of cinnamaldehyde with comparably low coumarin concentrations (<0.48 mg/g), and provide a large cinnamaldehyde depot for slow release applications.

Acrolein measurement and degradation in Dulbecco's Modified Eagle Medium: an examination of in-vitro exposure metrics.

Acrolein is a reactive α,ß-unsaturated aldehyde known for its adduction to endogenous biomolecules, resulting in initiation or exacerbation of several disease pathways. In-vitro systems are routinely used to elucidate the cytotoxic or mechanistic role(s) of acrolein in pathogenesis. Nevertheless, the half-life of acrolein in biological or in-vitro systems, e.g. blood or culture media, has not been well characterized. Since in-vitro cytotoxic and mechanistic investigations routinely expose cultures to acrolein from 1 hour to 72 hours, we aimed to characterize the half-life of acrolein in culture medium to ascertain the plausible exposure window. Half-life determinations were conducted in low-serum DMEM at room temperature and 37 °C, both with and without H9c2 cells. For quantitative assessment, acrolein was derivatized to a fluorescent 7-hydroxyquinoline method validated in-house and assessed via fluorescent spectroscopy. In closed vessel experiments at room temperature, acrolein in DMEM was reduced by more than 40% at 24 hours, irrespective of the initial concentration. Expectedly, open vessel experiments demonstrated accelerated depletion over time at room temperature, and faster still at 37 °C. The presence of cells tended to further accelerate degradation by an additional 15-30%, depending on temperature. These results undermine described experimental exposure conditions stated in most in-vitro experiments. Recognition of this discrepancy between stated and actual exposure metrics warrant examination of novel alternative objective and representative exposure characterization for in-vitro studies to facilitate translation to in-vivo and in-silico methods.

Acrolein Yields in Mainstream Smoke From Commercial Cigarette and Little Cigar Tobacco Products.

INTRODUCTION: Many carbonyls are produced from the combustion of tobacco products and many of these carbonyls are harmful or potentially harmful constituents of mainstream cigarette smoke. One carbonyl of particular interest is acrolein, which is formed from the incomplete combustion of organic matter and the most significant contributor to non-cancer respiratory effects from cigarette smoke. Sheet-wrapped cigars, also known as "little cigars," are a type of tobacco products that have not been extensively investigated in literature. METHODS: This study uses standard cigarette testing protocols to determine the acrolein yields from sheet-wrapped cigars. Sheet-wrapped cigar and cigarette products were tested by derivatizing the mainstream smoke with 2,4-dinitrophenylhydrazine (DNPH) solution and then quantifying the derivatives using conventional analytical systems. RESULTS: The results demonstrate that sheet-wrapped cigars can be tested for acrolein yields in mainstream smoke using the same methods used for the evaluation of cigarettes. The variability in the sheet-wrapped cigars and cigarettes under the International Organization for Standardization smoking regimen is statistically similar at the 95% confidence interval; however, increased variability is observed for sheet-wrapped cigar products under the Health Canada Intense (CI) smoking regimen. CONCLUSION: The amount of acrolein released by smoking sheet-wrapped cigars can be measured using standard smoking regimen currently used for cigarettes. The sheet-wrapped cigars were determined to yield similar quantity of acrolein from commercial cigarette products using two standard smoking regimens. IMPLICATIONS: This article reports on the measured quantity of acrolein from 15 commercial sheet-wrapped cigars using a validated standard smoking test method that derivatizes acrolein in the mainstream smoke with DNPH solution, and uses Liquid Chromatography/Ultra-Violet Detection (LC/UV) for separation and detection. These acrolein yields were similar to the levels found in the smoke from 35 commercial cigarette products measured in the same manner. Although sheet-wrapped cigar data were slightly more variable than those found for the cigarette data, this article reports that the production of acrolein is similar to cigarettes. The results demonstrate that sheet-wrapped cigars can be tested for acrolein yields in mainstream smoke using the same methods used for the evaluation of cigarettes.

Environmental and biological determination of acrolein using new cold fiber solid phase microextraction with gas chromatography mass spectrometry.

Acrolein is a pollutant released daily to the indoor environment from different sources. The present study reports the development of a simple and sensitive cold fiber solid phase microextraction sampling method for the determination of acrolein in exhaled air and indoor air by gas chromatography mass spectrometry. O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine was used as derivatizing agent supported on a 65-µm polydimethylsiloxane-divinylbenzene SPME fiber. An acrolein permeation tube at 326.25 ng min-1 rate was used to generate gaseous standards. The method shows good results for main validation parameters. The limits of detection and quantification were 2.88 and 5.08 µg m-3, respectively, for indoor analysis; and 2.40 and 3.79 µg m-3, respectively, for exhaled air analysis. The precision showed standard deviation ranges from 6.00 to 8.00% for intra-assay analyses and from 8.00 to 10.00% for inter-assay analyses. After optimizing the conditions, analyses of real samples were performed on indoor environments contaminated by cigarette smoke, or heated oil, including pastry shops, restaurants, churros stands, and closed parking cars located in the city of Belo Horizonte, Brazil. Acrolein breaths of exposed people were also determined. A good Pearson correlation coefficient (r = 0.901) was observed between the concentration of acrolein in indoor air and exhaled air, allowing to propose acrolein breath as environmental exposure biomarker. Graphical Abstract Cold fiber solid phase microextraction gas chromatography/mass spectrometry.

Analysis of formaldehyde and acrolein in the aqueous samples using a novel needle trap device containing nanoporous silica aerogel sorbent.

In this research, a needle trap device (NTD) packed with nanoporous silica aerogel as a sorbent was used as a new technique for sampling and analysis of formaldehyde and acrolein compounds in aqueous and urine samples. The obtained results were compared with those of the commercial sorbent Carboxen1000. Active sampling was used and a 21-G needle was applied for extraction of gas in the sample headspace. The optimization of experimental parameters like salt addition, temperature and desorption time was done and the performance of the NTD for the extraction of the compounds was evaluated. The optimum temperature and time of desorption were 280 °C and 2 min, respectively. The ranges of limit of detection, limit of quantification and relative standard deviation (RSD) were 0.01-0.03 µg L-1, 0.03-0.1 µg L-1 and 2.8-7.3%, respectively. It was found that the NTD containing nanoporous silica aerogel had a better performance. Thus, this technique can be applied as an effective and reliable method for sampling and analysis of aldehyde compounds from different biological matrices like urine, exhalation and so on.