Low Molecular Weight Carbonyl Research Articles

Rapid GC-MS based metabolic profiling of Capsicum annuum L. seeds at different phases of germination

Seed germination is the most critical stage of the life cycle of a plant. Metabolic regulation is significant during the course of seed germination for the establishment of seedlings. Upon imbibition, the dry and fully developed seeds undergo the release of various organic molecules, such as low molecular weight carbonyl compounds in the form of gases and volatiles, as well as water-soluble organic components like enzymes and polysaccharides. Volatile organic compounds may impart both positive and negative influences on seed germination. A metabolite profiling approach based on gas chromatography−mass spectrometry (GC-MS) was used to investigate time-dependent metabolic changes during the germination of Capsicum annuum L. cv. ‘Bullet’. This study aimed to identify bioactive compounds from the methanolic extract of dry, imbibed, germinating seeds and young seedlings of the ‘Bullet’ cultivar of C. annuum L. by GC-MS. A total of 56 distinct categories of compounds were identified in dry seeds, while fully absorbed seeds contained 53 compounds. In the germinating seed, 52 compounds were identified. With regard to immature seedlings, a total of 28 compounds were identified. The analysis revealed that each stage has a unique bio-constituent; only five compounds were detected in all extracts.

Modification of low-density lipoproteins by low molecular weight carbonyl products of free-radical oxidation of lipids and carbohydrates plays a key role in atherosclerotic lesion of the vascular wall and in endothelial dysfunction

The review presents evidence of the participation of low-density lipoproteins (LDL) modified by low molecular weight dicarbonyl compounds formed during freeradical oxidation of lipids (malondialdehyde) and carbohydrates in the development of endothelial dysfunction and atherosclerotic vascular lesions. The authors believe that it is they, and not oxidized (hydroperoxide-containing) LDL, that are the main factors of pathogenesis. The role of dicarbonyl-modified LDL in LOX-1 dependent induction of processes leading to the development of endothelial dysfunction is discussed. The results of studies proving that damage to the glycocalyx (a layer of macromolecules that prevent the development of endothelial dysfunction) covering the luminal surface of the endothelium is caused by hyperproduction of reactive oxygen species. Ways of pharmacological correction of free-radical oxidation processes are discussed, due to which inhibition of atherogenesis and diabetogenesis can be achieved.

Assessing Impacts of Additives on Particulate Matter and Volatile Organic Compounds Produced from the Grilling of Meat

Cooking fumes are an important source of volatile organic compounds (VOCs), particulate matter (PM), and carbonyl compounds. The additive is wildly applied in grilling meat for flavor improvement. However, the effects of additives on cooking fumes emissions, such as volatile organic compounds (VOCs), particulate matter (PM), and carbonyl compounds, in meat grilling have not been studied. The impact of four additives, including white pepper, salt, garlic powder, and compound marinade, on the emission characteristics of cooking fumes from the grilling meat was investigated. The concentrations of VOCs and carbonyl compounds in the cooking fumes were analyzed by TD-GC/MS and HPLC, respectively. The PM emission characteristics (mass concentration and size distribution) were measured by DustTrak DRX aerosol monitor in real-time. Results showed that the application of white pepper, salt, garlic powder, and mixed spices could significantly reduce the total particles mass concentration (TPM) emissions during meat-grilling by 65.07%, 47.86%, 32.87%, and 56.01%, respectively. The mass concentration of PM during meat-grilling reached maximum values ranging from 350 to 390 s and gradually fell at the final stages of grilling. The total concentration of 22 representative VOCs emitted from the grilling was significantly increased in grilling meat marinated with compound additives. Aromatic hydrocarbons were the predominant VOCs species, followed by ketone compounds. During the grilling process, formaldehyde, acetaldehyde, propionaldehyde, and acetone were major carbonyl compounds. The low molecular weight carbonyl compounds (C1–C3) in cooking fumes were dominant carbonyl compounds.

Adsorption of neutral and negatively charged low-molecular-weight carbonyls in reverse osmosis permeates by ion-exchange resins

Reverse osmosis (RO) has been increasing widely used in water and wastewater treatment to provide high-quality water, such as in industrial pure water production and municipal (non)potable water reuse. However, some low-molecular-weight (LMW) compounds, such as LMW carbonyls, penetrate through RO membranes and are present in the RO permeate, resulting in potential risk to human health or industrial production. Ion-exchange (IX) resins are widely used to help eliminate residual LWM organic compounds from RO permeates, but their elimination performance for carbonyls is not well understood. In this study, seven commercially available resins were employed to explore the adsorption performance for the elimination of representative carbonyls in RO permeate. In general, the adsorption performance of selected resins with regular polymer composition, pore structure and functional group was poor for LMW neutral carbonyl compounds, but efficient for carboxylic acids (number of carbon atoms is less than 4). Among target carboxylic acids, the gel-N+(CH3)3 resin exhibited rapid adsorption kinetics, performing better in the removal of LMW carboxylic acids with shorter alkyl chains and more carboxyl groups. In particular, binary carboxylic acids were adsorbed 3–5 times faster on resins compared with their monoacid counterparts. Charge density was the dominant factor affecting the adsorption performance of carbonyl compounds, followed by hydrophobicity, molecular chain length, and the presence of H attached to the carbonyl C. This study implies that neutral carbonyls cannot be efficiently eliminated by IX resin, and green oxidation processes, such as vacuum UV oxidation, are suggested for the conversion of such compounds to readily removable negatively charged carboxylic acids.

Nitrogen Oxides (NOx) in the Arctic Troposphere at Ny-Ålesund (Svalbard Islands): Effects of Anthropogenic Pollution Sources

Atmospheric measurements of nitrogen oxides (NOx = NO + NO2), ozone (O3) and other constituents were carried out during three field campaigns (29 March–30 April 2010, 1–26 April 2011, 18 May–8 October 2015) at Ny-Ålesund. The study focused on the variability of important O3 precursors, such as NOx, in the Arctic troposphere, and on the impact from anthropogenic sources on their measured concentrations: higher NO and NO2 levels were mostly associated with the lowest wind speeds and northern directions, indicating local pollution. Long-range transported sources from Russia and Europe were also identified with an occurrence of high NOx levels. Several ozone depletion events were observed and associated to winds blowing from the north-west direction (Arctic Ocean). Most of these events were connected to the lower NO and NO2 concentrations. Measurements of halogen and low molecular weight carbonyl compounds in 2010 and 2011, respectively, showed variable effects during the ozone depletion events. Other data, such as high time-resolved radon progeny measurements, were used in 2015 to identify source tracking and transport of air masses, local effects and atmospheric stability dynamics that could influence the NOx concentrations at Ny-Ålesund.

Fingerprinting of volatile organic compounds for quick assessment of vigour status of seeds

AbstractSeed is a fertilized mature ovule, which possesses an embryonic plant. When the dry, mature seeds are subjected to imbibition, they release a wide range of organic substances, which include low molecular weight carbonyl compounds (gases and volatiles) and water-soluble organic substances (enzymes and polysaccharides). The volatile organic compounds (VOCs) are molecules of low molecular weight (300 g mol−1) and high vapour pressure (0.01 kPa at 20°C) and include diverse chemical compounds. The nature and emission kinetics of volatiles produced from seeds vary, depending on the moisture content of the seeds. Orthodox seeds stored at ‘low seed moisture content’ undergo seed deterioration, predominantly due to lipid peroxidation, initiated by autoxidation or enzymatic oxidation of unsaturated or polyunsaturated fatty acids. This peroxidation leads to emission of volatile compounds. The quantity of VOCs emitted is positively correlated with the advancement of seed deterioration. With respect to the seed germination process, exposure of seeds to ‘high moisture conditions’ leads to increased respiration, triggers glycolysis and mobilization of storage reserves, resulting in the emission of volatile metabolic products. The quantity of VOCs emitted on commencement of metabolic activity in germinating seeds depends on (1) vigour status and (2) amount of storage reserves. Since it has been established that there is a significant difference between high and low vigour seeds with respect to quantity and profile of VOCs emitted, there is great potential for utilizing the VOC profile to obtain a quick and reproducible test of vigour status of crop seeds. In order to harness the VOC profile for quick assessment of vigour status of seeds, research has to be taken up to develop standard protocols for fingerprinting of VOCs for the purpose of seed vigour assessment and to fix the standard volatile biomarker(s) specific to crop and vigour status of seeds.

Gaseous and heterogeneous reactions of low-molecular-weight (LMW) unsaturated ketones with O3: Mechanisms, kinetics, and effects of mineral dust in tropospheric chemical processes

Mineral dust has a significant effect on the atmospheric heterogeneous chemistry and environmental risk prediction of VOCs. In this work, a comprehensive theoretical study for the gaseous and heterogeneous reactions process of four Low-Molecular-Weight (LMW) unsaturated ketones with O3 has been provided for the first time. SiO2 is the main component of mineral dust, which shows better adsorption performance of these ketones and represents a good sinking of atmospheric LMW oxygenated VOCs. The gaseous reactions of LMW unsaturated ketones with O3 are closely related to the formation of some strong oxidants and air pollution behaviors. The heterogeneous reactions of these ketones onto the surface of available mineral aerosols may compete with the corresponding gas phase reactions, especially in arid and semi-arid areas with frequent dust storms. Organic hydroperoxides and LMW carbonyl compounds generated in the title reactions may change the properties of aerosols, which have essential impacts on tropospheric chemistry and climate. The presence of SiO2 could accelerate the reactions of LMW unsaturated ketones with O3 without changing their degradation mechanism. It also should be emphasized that the promoting effect of SiO2 clusters to CH2OO + H2O has been found in our computation. This may explain the high product yields of HMHP and H2O2 detected on SiO2 particles in the experiment. The effect of mineral particles on the O3-initiated reactions has been probed at the molecular level and the pollution mechanism of VOCs has been better understood.

Evaluation of the reduction in carbonyl emissions and ozone formation potential from the exhaust of a heavy-duty diesel engine by hydrogen-diesel dual fuel combustion

In this study, diesel engine was fueled by multi-fuels, including conventional diesel and 0, 0.6 and 1.2 vol% hydrogen and operated at low to high engine loads. Low molecular weight carbonyls, such as formaldehyde, acetaldehyde, and acetone, contributed 79.2–87.2% of total carbonyl compounds which are the more prominent when the engine operated at low load. With 0.6 and 1.2 vol% of hydrogen addition, formaldehyde decreased 10.4–10.9% at idling condition. As the load increases 25, 50 and 75%, the formaldehyde decreased by 2.93–25.1, 5.91–25.8 and 2.28–40.5%, respectively. The same reduction phenomenon can also be observed from acrolein, acetone, propionaldehyde, crotonaldehyde and 2-butanone & butyraldehyde emissions. The highest ozone-formation potential (OFP) from multi-pollution emissions was found at idling operation. The high OFP could be reduced by increasing hydrogen additions and eventually approached the lowest level with 1.2 vol% hydrogen addition at middle to high engine load. Nevertheless, the diesel engine with hydrogen addition could reduce a certain amount of CBC emission and OFP at engine idling operation.

An Assessment of Indoor Air Quality before, during and after Unrestricted Use of E-Cigarettes in a Small Room.

Airborne chemicals in the indoor environment arise from a wide variety of sources such as burning fuels and cooking, construction materials and furniture, environmental tobacco smoke as well as outdoor sources. To understand the contribution of exhaled e-cigarette aerosol to the pre-existing chemicals in the ambient air, an indoor air quality study was conducted to measure volatile organic compounds (including nicotine and low molecular weight carbonyls), polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines and trace metal levels in the air before, during and after e-cigarette use in a typical small office meeting room. Measurements were compared with human Health Criteria Values, such as indoor air quality guidelines or workplace exposure limits where established, to provide a context for potential bystander exposures. In this study, the data suggest that any additional chemicals present in indoor air from the exhaled e-cigarette aerosol, are unlikely to present an air quality issue to bystanders at the levels measured when compared to the regulatory standards that are used for workplaces or general indoor air quality.

Production and characterization of refined oils obtained from Indian oil sardine (Sardinella longiceps).

Crude Sardinella longiceps oil was refined in different stages such as degumming, neutralization, bleaching, and deodorization. The efficiency of these processes was evaluated on the basis of free fatty acid (FFA), peroxide (PV), p-anisidine (pAV), total oxidation (TOTOX), thiobarbituric acid reactive species (TBARS) values, Lovibond CIE-L*a*b* color analyses, and (1)H NMR or GC-MS experiments. The utilities of NMR-based proton signal characteristics as new analytical tools to understand the signature peaks and relative abundance of different fatty acids and monitoring the refining process of fish oil have been demonstrated. Phosphoric acid (1%) was found to be an effective degumming reagent to obtain oil with the lowest FFA, PV, pAV, TOTOX, and TBARS values and highest color reduction. Significant reduction in the contents of hydrocarbon functionalities as shown by the decrease in proton integral in the characteristic (1)H NMR region was demonstrated by using 1% H3PO4 during the course of the degumming process. A combination (1.25:3.75%) of activated charcoal and Fuller's earth at 3% concentration for a stirring time of 40 min was found to be effective in bleaching the sardine oil. This study demonstrated that unfavorable odor-causing components, particularly low molecular weight carbonyl compounds, could successfully be removed by the refining process. The alkane-dienals/alkanes, which cause unfavorable fishy odors, were successfully removed by distillation (100 °C) under vacuum with aqueous acetic acid solution (0.25 N) to obtain greater quality of refined sardine oil, a rich source of essential fatty acids and improved oxidative stability. The present study demonstrated that the four-stage refinement process of sardine oil resulted in a significant improvement in quality characteristics and nutritional values, particularly n-3 PUFAs, with improved fish oil characteristics for use in the pharmaceutical and functional food industries.

Spatial distributions of and diurnal variations in low molecular weight carbonyl compounds in coastal seawater, and the controlling factors

We studied the spatial distributions of and the diurnal variations in four low molecular weight (LMW) carbonyl compounds, formaldehyde, acetaldehyde, propionaldehyde, and glyoxal, in coastal seawater. The samples were taken from the coastal areas of Hiroshima Bay, the Iyo Nada, and the Bungo Channel, western Japan. The formaldehyde, acetaldehyde, and glyoxal concentrations were higher in the northern part of Hiroshima Bay than at offshore sampling points in the Iyo Nada and the Bungo Channel. These three compounds were found at much higher concentrations in the surface water than in deeper water layers in Hiroshima Bay. It is noteworthy that propionaldehyde was not detected in any of the seawater samples, the concentrations present being lower than the detection limit (1nanomole per liter (nM)) of the high performance liquid chromatography (HPLC) system we used. Photochemical and biological experiments were performed in the laboratory to help understand the characteristic distributions and fates of the LMW carbonyl compounds. The primary process controlling their fate in the coastal environment appears to be their biological consumption. The direct photo degradation of propionaldehyde, initiated by ultraviolet (UV) absorption, was observed, although formaldehyde and acetaldehyde were not degraded by UV irradiation. Our results suggest that the degradation of the LMW carbonyl compounds by photochemically formed hydroxyl radicals is relatively insignificant in the study area. Atmospheric deposition is a possible source of soluble carbonyl compounds in coastal surface seawater, but it may not influence the carbonyl concentrations in offshore waters.

Carbonyl emissions generated by a (SI/HCCI) engine from winter grade commercial gasoline

The analysis of carbonyl species of a gasoline fuelled Spark-Ignition and Homogeneous Charge Compression Ignition (SI/HCCI) engine operating modes was performed upstream and downstream of a three way catalyst (TWC) converter. All data were obtained during steady-state, fully warmed-up operation at different engine conditions, using a winter grade commercial gasoline containing 2%w/w ethanol (C2H5OH). Qualitative and quantitative analysis of carbonyl compounds in exhaust gases were performed using 2,4-dinitrophenylhydrazine (DNPH)-high-performance liquid chromatography (HPLC). The major carbonyl compounds detected in the collected samples were acetaldehyde, acrolein, benzaldehyde and m-tolualdehyde. Depending on the engine operation conditions, the percentage contribution of the carbonyl compounds to the total hydrocarbons emission in this study lies between 2.7% and 5.2%. Formation of low molecular weight carbonyl compounds was more prominent when the engine operated at low load HCCI mode (low combustion temperature), while aromatic aldehydes were more significant in the case of SI mode operation, in which the combustion temperature is relatively high compared to the temperature from low load HCCI mode.Even though, the catalyst reduced the hydrocarbons emission effectively, including the carbonyls, there is no significant effect on the emission of acetaldehyde and acrolein emissions.

Carbonyl Levels and Personal Exposures in Large Shopping Malls of Nanchang, China

Ambient levels of carbonyl compounds and their possible sources, diurnal variations, and personal exposure were investigated in four types of large shopping malls (including department store, supermarket, and bookstore and furniture store) in urban district of Nanchang, China. Eighteen out of the twenty target carbonyls were detected in summer samples while only fifteen carbonyls were detected in winter samples. The descending order of total mean concentration was furniture store (102.2 ± 22.9 µg m−3)>supermarket (84.2 ± 15.7 µg m−3)>department store (79.0 ± 21.1 µg m−3)>book store (68.6 ± 14.5 µg m−3). A significant correlation between the concentration of the low molecular-weight (LMW) carbonyl compounds (<C5) and ozone was found in summer. The diurnal curve exhibited a higher peak at the morning hour and a lower peak at the evening hour except for acetaldehyde, which peaked at the afternoon hour in winter. The indoor concentrations of LMW carbonyl compounds were found to be higher than their outdoor counterparts with only a few exceptions. For some high molecular weight (HMW) carbonyls (≥C5) especially for benzaldehyde and p-tolualdehyde which might have stronger outdoor source (e.g., vehicle exhaust), had resulting in the Indoor/Outdoor ratios below 1. The personal exposures showed that large shopping malls in Nanchang were important microenvironments for exposure to formaldehyde and acetaldehyde.

Observations of nonmethane organic compounds during ARCTAS − Part 1: Biomass burning emissions and plume enhancements

Abstract. Mixing ratios of a large number of nonmethane organic compounds (NMOCs) were observed by the Trace Organic Gas Analyzer (TOGA) on board the NASA DC-8 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaign. Many of these NMOCs were observed concurrently by one or both of two other NMOC measurement techniques on board the DC-8: proton-transfer-reaction mass spectrometry (PTR-MS) and whole air canister sampling (WAS). A comparison of these measurements to the data from TOGA indicates good agreement for the majority of co-measured NMOCs. The ARCTAS study, which included both spring and summer deployments, provided opportunities to sample a large number of biomass burning (BB) plumes with origins in Asia, California and central Canada, ranging from very recent emissions to plumes aged one week or more. For this analysis, BB smoke interceptions were grouped by flight, source region and, in some cases, time of day, generating 40 identified BB plumes for analysis. Normalized excess mixing ratios (NEMRs) to CO were determined for each of the 40 plumes for up to 19 different NMOCs or NMOC groups. Although the majority of observed NEMRs for individual NMOCs or NMOC groups were in agreement with previously-reported values, the observed NEMRs to CO for ethanol, a rarely quantified gas-phase trace gas, ranged from values similar to those previously reported, to up to an order of magnitude greater. Notably, though variable between plumes, observed NEMRs of individual light alkanes are highly correlated within BB emissions, independent of estimated plume ages. BB emissions of oxygenated NMOC were also found to be often well-correlated. Using the NCAR Master Mechanism chemical box model initialized with concentrations based on two observed scenarios, fresh Canadian BB and fresh Californian BB, decreases are predicted for the low molecular weight carbonyls (i.e. formaldehyde, acetaldehyde, acetone and methyl ethyl ketone, MEK) and alcohols (i.e. methanol and ethanol) as the plumes evolve in time, i.e. the production of these compounds is less than the chemical loss. Comparisons of the modeled NEMRs to the observed NEMRs from BB plumes estimated to be three days in age or less indicate overall good agreement.

Photochemical production of formaldehyde, acetaldehyde and acetone from chromophoric dissolved organic matter in coastal waters

Abstract Low molecular weight carbonyl compounds are produced photochemically from chromophoric dissolved organic matter (CDOM) in natural waters. Photoproduction rates for formaldehyde, acetaldehyde and acetone were measured in the laboratory using a pre-column 2,4-dinitrophenylhydrazine derivitization HPLC method as a function of optical properties (absorption coefficient, spectral slope) and irradiation time. Rates decreased linearly with decreasing absorption coefficient at 350 nm ( a (350 nm)), a measure of CDOM levels, with substantial variability in low a (350 nm) beach waters. Apparent quantum yields ( Θ ) were unchanged for a (350 nm) = 2–16 m −1 , but increased rapidly (×5) for beach waters with low a (350 nm) values. Θ increased linearly with increasing spectral slope for beach waters, consistent with enhanced production efficiency with photobleaching of CDOM in coastal waters. Θ trends with oxygen and molecular reaction probes (hydroxyl radical scavengers and producers) suggested a combination of direct photolysis and singlet oxygen quenching as primary production mechanisms.

Photocatalytic degradation of organic paint constituents-formation of carbonyls

Titanium dioxide is frequently used in outdoor building materials to degrade, when activated by solar light, organic and inorganic pollutants in air. In this context, a promising application is the use of TiO 2 in photocatalytic paints. The development of doped TiO 2 allowing activation by visible light opens up a wide range for air purifying applications in indoor environments too. Indoors however, formation and accumulation of by-products might represent in the long term a risk for human health and affect comfort and well being. In the past, formation of low-molecular weight carbonyls as formaldehyde and acetaldehyde was observed. The scope of this study was to identify the sources for the carbonyl compounds and propose a mechanism for their formation. A photocatalytic paint of known composition was irradiated repeatedly for a period of 14 days and carbonyl formation was measured. In addition, components of the paint were irradiated separately as single compounds in the presence/absence of titanium dioxide. Formaldehyde, acetaldehyde, propanal and acetone (in decreasing order of concentration) were the main carbonyls identified. Hexanal, heptanal and octanal were measured in lower concentrations. Formation of carbonyls decreases in the course of the irradiation. Organic polymers as paint constituents were found as the main source for the formation of the carbonyls. A mechanism based on radical chain reactions for the degradation of the organic paint matrix is proposed. The study discusses the potential risk of accumulation of carbonyls in confined spaces/indoor environments and the need to develop user friendly, low emitting photo catalytic materials.

Energy metabolism, proteotoxic stress and age-related dysfunction – Protection by carnosine

This review will discuss the relationship between energy metabolism, protein dysfunction and the causation and modulation of age-related proteotoxicity and disease. It is proposed that excessive glycolysis, rather than aerobic (mitochondrial) activity, could be causal to proteotoxic stress and age-related pathology, due to the generation of endogenous glycating metabolites: the deleterious role of methylglyoxal (MG) is emphasized. It is suggested that TOR inhibition, exercise, fasting and increased mitochondrial activity suppress formation of MG (and other deleterious low molecular weight carbonyl compounds) which could control onset and progression of proteostatic dysfunction. Possible mechanisms by which the endogenous dipeptide, carnosine, which, by way of its putative aldehyde-scavenging activity, may control age-related proteotoxicity, cellular dysfunction and pathology, including cancer, are also considered. Whether carnosine could be regarded as a rapamycin mimic is briefly discussed.

LC-MS Analysis of Low Molecular Weight Carbonyl Compounds as 2,4-Dinitrophenylhydrazones Using Negative Ion Mode Electronspray Ionization Mass Spectrometry

Organic compounds in the environment, such as pesticides, degrade into inorganics via transformation into carbonyl compounds, such as formaldehyde, acetaldehyde, and acetone. 2, 4-Dinitrophenylhydrazones of 37 carbonyl compounds were prepared with 2, 4-dinitrophenyl hydrazine (DNPH). Their ESI negative spectra and EI positive spectra were obtained using an HPLC-mass spectrograph. EI positive spectra showed more ions than ESI negative spectra except in the case of two hydrazones. Molecular ions (M+) of carbonyl-DNPHs appeared as a base peak in the EI positive spectra in the case of all but 8 hydrazones. Many significant ions for the identification of a specific carbonyl compound are obtained by ESI negative spectra. Analysis of acetone in various waste waters was successfully conducted using a newly developed ESI negative spectroscopy method-levels found in the samples ranged from 2.1 mg/L to135.0 mg/L. Results of similar tests of the rate of acetone degradation in various water samples showed that acetone in moat water degraded completely after 18 days, whereas 70% of the acetone remained in pure water after 65 days, suggesting that microorganisms may play an important role in the degradation of carbonyl compounds in the environment.

Characteristics and personal exposures of carbonyl compounds in the subway stations and in-subway trains of Shanghai, China

Carbonyl compounds including their concentrations, potential sources, diurnal variations and personal exposure were investigated in six subway stations and in-subway trains in Shanghai in June 2008. The carbonyls were collected onto solid sorbent (Tenax TA) coated with pentafluorophenyl hydrazine (PFPH), followed by solvent extraction and gas chromatography (GC)/mass spectrometry (MS) analysis of the PFPH derivatives. The total carbonyl concentrations of in-subway train were about 1.4–2.5 times lower than in-subway stations. A significant correlation ( R > 0.5, p < 0.01) between the concentrations of the low molecular-weight carbonyl compounds (<C 5) and ozone was found in the subway stations. The diurnal variations in both the subway station and in-subway train showed that the concentrations of most carbonyls were much higher in the morning rush hour than in other sampling periods. Additionally, pronounced diurnal variations of acetaldehyde concentration before and after the evening peak hour in the subway train suggested that passengers contributed to high acetaldehyde levels. The personal exposure showed that the underground subway stations were important microenvironment for exposure to formaldehyde and acetaldehyde.

HPLC-MS Determination of Acrolein and Acetone Generated from 13C3 -Labeled Glycerol Added to Cigarette Tobacco Using Two Machine-Smoking Regimes

Abstract The extent of blend glycerol degradation in a burning cigarette to form acrolein and acetone has been quantitatively determined by the addition of glycerol-13C3 to three styles of a leading commercial cigarette brand. Multiple Cambridge pads soaked with a solution of 2,4-dinitrophenylhydrazine (DNPH) were employed to trap hydrazone derivatives of low molecular weight carbonyl compounds in both mainstream and sidestream smoke. High performance liquid chromatography coupled with negative ion mass spectrometry was used to isolate DNPH derivatives of the volatile carbonyl products of combustion and to ascertain their concentration. Acrolein, acetone, and propionaldehyde were the principal compounds of interest. The DNPH derivatives of acrolein-13C3 and acetone-13C3 were independently synthesized, and they served as external standards for absolute quantitation. The cost of fully labeled propionaldehyde precluded its use in this study. The brand styles selected for study represent the cigarette design features that are most prevalent in the U.S. market today and afford a representative range of standardized “tar” yields (14, 10, and 5 mg/cig, respectively by the Cambridge Filter Method). The brand styles studied are part of a commercial cigarette brand family that does not contain additives to the tobacco blend, including glycerol. Mainstream smoke was generated by an automated smoking machine employing the standard Cambridge Filter Smoking Regime and a more intense regime requiring larger, more frequent puffs and 100% vent blocking that is specified for regulatory purposes by the Canadian federal government. The research indicated that only a small fraction of added glycerol (~0.25%-0.30%, w/w) was converted to the two compounds of interest, with the larger portion generally observed in sidestream smoke. Less than 0.1% of the added glycerol was converted to acrolein in mainstream smoke for all cigarette designs and smoking regimes studied.