Proportions Of Aldehydes Research Articles

A longitudinal study of volatile organic compounds from cooking under ventilation and purification intervention: Health risk assessment and odor nuisance control

Cooking oil fumes (COFs) expose occupants to hazardous air pollutants and nuisance odors, hence the real controlling effects of different intervention methods deserve to be explored. This longitudinal study conducted year-round field measurements in 10 apartments to explore the synergistic effects of dual ventilation and purification interventions on the exposure level, odor intensity, and health risk control of gaseous organic compounds during cooking. Gas chromatography-mass spectrometry (GC‒MS) and high performance liquid chromatography (HPLC) were used for quantification of volatile organic compounds (VOCs) and carbonyls. A total of 59 VOCs were detected during cooking, and the average ΣVOC concentrations in summer, the transition seasons, and winter were 483.16 μg/m3, 233.97 μg/m3, and 282.82 μg/m3, respectively, and the proportion of aldehydes was approximately 50 %. The small temperature differences between the indoors and outdoors led to a 24 % reduction in the effective air changes per hour (ACH) in the summer compared with that in other seasons. The average estimated carcinogenic risks of formaldehyde, acetaldehyde and benzene were 9.20 × 10−5, 1.11 × 10−5, and 6.05 × 10−6, respectively, for daily cooking conditions. It is difficult to guarantee a healthy cooking environment by mechanical ventilation alone. The inhalation carcinogenic risk of these 3 hazardous VOCs was reduced by approximately 130.9 % under air purification intervention but was still greater than 1E-6. The noncarcinogenic risk of acrolein under the different intervention modes ranged from 69.8 to 84.9. Moreover, acetaldehyde and hexanal were found to be the key odorants in kitchen. When the effective exhaust air rate was greater than 12 m3/min with air purifier in operation, the average inhalation health risk was 1.05–1.78 times that before cooking, and more than half of the users would not smell obvious odors during the cooking process. This study quantifies the effectiveness of the synergetic control strategy of independent purification modules combine with kitchen mechanical ventilation, with a view to implementing a healthy & comfortable living environment.

Exhaled VOC Biomarkers from Rats Injected with PMs from Thirty-One Major Cities in China.

Particulate matter (PMs) of different origins can cause diverse health effects. Here, a homemade box was used to facilitate real-time measurements of breath-borne volatile organic compounds (VOCs) by gas chromatography-ion mobility spectrometry. We have tracked exhaled VOC changes in 228 Wistar rats that were injected with water-soluble PM suspension filtrates (after 0.45 μm) from 31 China cities for 1 h to up to 1-6 days during the experiments. Rats exposed to the filtrates exhibited significant changes in breath-borne VOCs within hours, featuring dynamic fluctuations in the levels of acetone, butan-2-one, heptan-2-one-M, acetic acid-M, and ethanol. Subsequently, on the fifth to sixth day after the injection, there was a notable increase in the proportion of aldehydes (including hexanal-M, hexanal-D, pentanal, heptanal-M, and (E)-2-hexenal). The 10 dynamic VOC fingerprint patterns mentioned earlier showcased the capability to indirectly differentiate urban PM toxicity and categorize the 31 cities into four distinct groups based on their health effects. This study provides valuable insights into the mechanisms of exhaled VOCs and underscores their critical role as biomarkers for differentiating the toxicity of different PMs and detecting the early signs of potential diseases. The results from this work also provide a scientific basis for city-specific air pollution control and policy development.

Selective control in the reductive amination of benzaldehyde towards corresponding amines over COF supported Pt, Pd, and Rh catalysts

Since selective control in catalytic reductive aminations of aldehyde for the synthesis of functional amines was highly valued, we developed three kinds of COFs supported catalysts (Pt/COF, Pd/COF, and Rh/COF) for selectively catalytic reductive amination of benzaldehyde. Results indicated that Pd/COF and Pt/COF exhibited good selectivity towards secondary amines with a 1.2/1 M proportion of aldehyde and ammonia, while Rh/COF catalyst can selectively convert benzaldehyde to secondary imine with an excellent yield of 90%. Furthermore, an improved yield of primary amine could be obtained over Rh/COF catalyst with a 1.2/60 M proportion of aldehyde and ammonia.

Chemometric approaches for the optimization of headspace-solid phase microextraction to analyze volatile compounds in coriander (Coriandrum sativum L.)

Headspace-solid phase microextraction (HS-SPME) conditions for the gas chromatography-mass spectrometry (GC-MS) analysis of volatiles in coriander aerial part were systematically optimized for the first time using chemometric approaches. Single factor test preliminarily determined the superior level of each parameter. Plackett-Burman factorial design further identified the three most significant variables (heating temperature > extraction time > CaCl2 amount). Then, Box-Behnken design of response surface methodology (RSM) was applied to obtain the optimal extraction conditions and corresponding model equation (R2 = 0.9793–0.9809). Verification results with less than 5% of relative standard deviations (RSDs) indicated that this extraction procedure had good repeatability and intermediate precision. A total of 67 volatiles were identified from coriander, mainly including aldehydes, alcohols, hydrocarbons and esters. Among them, the proportion of aldehydes was highest approximately 83.76%, and (E)-2-tetradecenal was the most abundant analyte, followed by (Z)-9-hexadecenal, 2-dodecenal and (E)-2-tridecenal. There were 21 characteristic volatiles with the odor activity values (OAVs) greater than 1, which contributed greatly to coriander flavor. Moreover, citrus aroma was the strongest scent, afterwards were fatty and unpleasant soapy odors. This research provided an advanced technical support for the extraction and analysis of coriander volatiles.

Effect of Lentinan on Lipid Oxidation and Quality Change in Goose Meatballs during Cold Storage.

The effects of different concentrations of lentinan (LNT) (0, 0.5, 1, 2 and 4%) on the oxidation characteristics and physicochemical properties of goose meatballs were investigated during different cold storage (4 °C) stages (3, 7 and 12 days). After adding LNT, the thiobarbituric acid reactive substances (TBARS) and total volatile base nitrogen (TVB-N) of goose meatballs significantly decreased compared to the LNT-free sample during cold storage, which indicated that LNT can inhibit the fat oxidation and the release of nitrogenous substances. Meanwhile, the presence of LNT makes microstructure of the goose meatball samples become denser during the whole storage time. The headspace solid phase microextraction gas chromatography-mass spectrometry (SPME-GC-MC) results showed that the proportion of aldehydes in the 4% LNT group reached 0 during storage, suggesting that high LNT concentration inhibits the formation of oxidized products in meat products. The sensory evaluation showed that the addition of LNT improved the color, appearance, flavor, and overall acceptance of goose meatballs, and the 2% LNT group had the highest score in overall acceptance. In summary, the addition of LNT could delay lipid oxidation and improve the quality of goose meatballs during cold storage.

Volatile fatty acid and aldehyde abundances evolve with behavior and habitat temperature in Sceloporus lizards.

Animal signals evolve by striking a balance between the need to convey information through particular habitats and the limitations of what types of signals can most easily be produced and perceived. Here, we present new results from field measures of undisturbed behavior and biochemical analyses of scent marks from 12 species of Sceloporus lizards to explore whether evolutionary changes in chemical composition are better predicted by measures of species behavior, particularly those associated with visual displays, chemoreception, and locomotion, or by measures of habitat climate (precipitation and temperature). We found that more active lizard species used fewer compounds in their volatile scent marks, perhaps conveying less specific information about individual and species identity. Scent marks from more active lizard species also had higher proportions of saturated fatty acids, and the evolution of these compounds has been tracking the phylogeny closely as we would expect for a metabolic byproduct. In contrast, the proportions of unsaturated fatty acids were better explained by evolutionary shifts in habitat temperature (and not precipitation), with species in warmer climates using almost no volatile unsaturated fatty acids. The proportion of aldehydes was explained by both behavior and environment, decreasing with behavioral activity and increasing with habitat temperature. Our results highlight the evolutionary flexibility of complex chemical signals, with different chemical compounds responding to different elements of the selective landscape over evolutionary time.

Effects of natural ingredients on the shelf life of chicken seasoning

The effects of the natural ingredients Angelica sinensis (AS) and Codonopsis pilosula (CP) on the shelf life of chicken seasoning were investigated. Color differences and sensory evaluation were used to indicate sensory differences. Changes in volatiles were monitored. The rate of increase in the color value a* of the AS and CP samples was lower than that in the control. Rancid flavor appeared later in the AS and CP samples than in the control. The levels of aldehydes, ketones, and alkenes increased during storage. A kinetic model was built based on the proportion of aldehydes (main marker), to predict shelf life. The predicted shelf life at room temperature was 60 days for the control, 114 days for AS, and 89 days for CP. The shelf life of chicken seasoning could be prolonged with AS and CP. This kinetic model can be used to predict the shelf life of chicken seasoning.

Subcritical liquefaction of lignocellulose for the production of bio-oils in ethanol/water system

Lignocellulose (20–40 mesh) was converted into bio-oils in ethanol with different concentrations (0, 20%, 40%, 60%, 80%, and 100%). The products were separated to obtain solid residues, heavy and light oils, and they were comprehensively characterized with a series of both chemical and spectral methods. Results indicated that the addition of ethanol enhanced the penetration of solvent into the rigid structure of lignocellulose. The highest bio-oil yield of 36.62% was obtained when the lignocellulose was liquified with 60% ethanol. The higher heating value of heavy oil decreased whereas that of light oil increased when more ethanol was used. 1H NMR analysis revealed that the addition of ethanol resulted in a high proportion of alcohols, ethers and esters, together with less aldehydes in the heavy oil. Meanwhile, the proportions of aldehydes in the light oil decreased with the increase of ethanol concentration.

Modeling rates of DOC degradation using DOM composition and hydroclimatic variables

AbstractThe fluvial fluxes of dissolved organic carbon (DOC) from peatlands form an important part of that ecosystem's carbon cycle, contributing approximately 35% of the overall peatland carbon budget. The in‐stream processes acting on the DOC, such as photodegradation and biodegradation, can lead to DOC loss and thus contribute CO2 to the atmosphere. The aim of this study was to understand what controls the rates of DOC degradation. Water samples from a headwater, peat‐covered catchment, were collected over a 23 month period and analyzed for the DOC degradation rate and dissolved organic matter (DOM) composition in the context of hydroclimatic monitoring. Measures of DOM composition included 13C solid‐state nuclear magnetic resonance spectroscopy, bomb calorimetry, and elemental analysis. Regression analysis showed that there was a significant role for the composition of the DOM in controlling degradation with degradation rates significantly increasing with the proportion of aldehyde and carboxylic acid functional groups but decreasing with the proportion of N‐alkyl functional groups. The highest rates of DOC degradation occurred when aldehyde functionality was at its greatest and this occurred on the recession limb of storm hydrographs. Including this knowledge into models of fluvial carbon fate for an 818 km2 catchment gave an annual average DOC removal rate of 67% and 50% for total organic carbon, slightly lower than previously predicted. The compositional controls suggest that DOM is primarily being used as a ready energy source to the aquatic ecosystem rather than as a nutrient source.

Oxidation of hydroxymethylpyrazines and hydroxylated phenyl compounds in a gas chromatography inlet

Large proportions of aldehydes were formed when hydroxymethylpyrazines, and benzyl- and cinnamyl alcohols were analysed by gas chromatography-mass spectrometry using a heated inlet with a used glass inlet liner.

The oxidation of aldehydes in aqueous solutions of cetomacrogol.

Abstract The oxidation of emulsions and solutions of five paraffinic aldehydes in aqueous solutions of cetomacrogol was measured manometrically at 25°. The rate of oxidation depends on the saturation of the dispersion and not on the concentrations of aldehyde and cetomacrogol except in so far as these control saturation. A method of expressing saturation, applicable to both solutions and emulsions is proposed. Differences between the oxidation rates of emulsions containing aldehydes of different chain length are shown to depend mainly on the proportion of aldehyde in the disperse phase.

The Volatile Composition of Kiyomi Peel Oil (Citrus unshiu Marcov×C. sinensis Osbeck) Cultivated in Korea

The volatile composition of Kiyomi peel oil cultivated in Korea was studied by using gas chromatography and gas chromatography-mass spectrometry. The peel oil from the Kiyomi fruit was prepared by using a cold-pressing extraction method. Among the 65 components quantified in Kiyomi oil, 25 terpene hydrocarbons and 40 oxygenated compounds were identified, with peak weight percentages measuring 94.5% and 4.9%, respectively. Limonene was the predominant compound (87.5%), followed by myrcene (2.4%), sabinene (0.9%), α-pinene (0.8%), β-sinensal (0.8%), (Z)-β-farnesene (0.7%), neryl acetate (0.6%), valencene (0.5%), α-farnesene (0.5%), and α-sinensal (0.5%). A unique characteristic of the volatile profile of the Kiyomi oil was the proportion of aldehydes (2.7%), which resulted from the relative abundance of α- and β-sinensal. Another unique characteristic of the Korean Kiyomi oil was its relative abundance of β-sinensal, (Z)-β-farnesene, neryl acetate, valencene, α-sinensal and nootkatone. Valencene and α- and β-sinensal were regarded as the influential components of Korean Kiyomi peel oil.

Reactions of carbonyl compounds with tervalent phosphorus reagents. Part 7. Benzaldehyde with chlorodiphenylphosphine in the presence of acetic acid

The reaction of chlorodiphenylphosphine (1a) with benzaldehyde in the presence of acetic acid has been re-examined. The final products have been isolated and identified as α-acetoxybenzyldiphenylphosphine oxide (4) and bis-α-(diphenylphosphinoyl)benzyl ether (5). The relative amounts of (4) and (5) formed are markedly influenced by the proportion of aldehyde in the reaction mixture.