ENVIRONMENTAL GEOCHEMISTRY AND HEALTH
·
2008
·Vol. 31
·期 1
·119-131
·
IF 1.086
Bu Qing Wei,Zhang Zhi Huan,Lu Song,He Feng Peng
Vertical distribution of both the concentration and composition of polycyclic aromatic hydrocarbons (PAHs) in ten profiles in Beijing has been investigated. The results showed that PAH concentrations and compositions in topsoil from different sampling sites were different. PAH concentrations were much higher in topsoil of the investigated urban area, industrial region, and paddy field with wastewater irrigation than in other areas. Moreover, PAH concentrations in topsoil were much higher than those at greater depth, where the concentrations were relatively consistent in most soil profiles. The fingerprints of PAHs in the samples from topsoil (0–30 cm) in the same profiles were similar and were obviously different from those at greater depth, suggesting that PAH sources were consistent in topsoil samples and were discriminating between topsoil and deeper soils. PAHs in topsoil mainly arose from mixed sources of combustion of liquid fuel, coal, and/or wood, as well as wastewater irrigation, while those at greater depth were derived from soil genesis and the process of soil formation.
研究领域:
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Science of Animal Resources
·
2021
·
IF 2.471
Xiao-Guang Dong,Li-Bing Gao,Hai-Jun Zhang,Jing Wang,Kai Qiu,Guang-Hai Qi,Shu-Geng Wu
This study discriminated fatty acid profile and flavor characteristics of BeijingYou Chicken (BYC) as a precious local breed and Dwarf Beijing You Chicken (DBYC)eggs. Fatty acid profile and flavor characteristics were analyzed to identifydifferences between BYC and DBYC eggs. Four classification algorithms were usedto build classification models. Arachidic acid, oleic acid (OA), eicosatrienoicacid, docosapentaenoic acid (DPA), hexadecenoic acid, monounsaturated fattyacids (MUFA), polyunsaturated fatty acids (PUFA), unsaturated fatty acids (UFA)and 35 volatile compounds had significant differences in fatty acids andvolatile compounds by gas chromatography-mass spectrometry (GC-MS)(p<0.05). For fatty acid data, k-nearest neighbor (KNN) and supportvector machine (SVM) got 91.7% classification accuracy. SPME-GC-MS datafailed in classification models. For electronic nose data, classificationaccuracy of KNN, linear discriminant analysis (LDA), SVM and decision tree wasall 100%. The overall results indicated that BYC and DBYC eggs could bediscriminated based on electronic nose with suitable classification algorithms.This research compared the differentiation of the fatty acid profile andvolatile compounds of various egg yolks. The results could be applied toevaluate egg nutrition and distinguish avian eggs.
研究领域:
食品科学
·
化学计量学
·
动物科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Science China-Chemistry
·
2024
·
IF 10.4
Yang Ning,Gong Chu,Zhang Dongmei,Gao Xufeng,Han Lifeng,Fu Pingqing,Zhang Xinxing
Humic-like substances (HULIS), a class of macromolecular photosensitizers, are major components of light-absorbing aerosols in the atmosphere. Due to the amphiphilic nature of HULIS, they tend to appear at the air-water interface of atmospheric water. However, there have been limited studies on the photosensitized chemistry of HULIS at the air-water interface owing to the lack of methods with high interface selectivity. Here, a unique field-induced droplet ionization mass spectrometry (FIDI-MS) technique was used to investigate the photosensitized chemistry of several samples at the air-water interface. These samples include commercially available humic acid and the PM 2.5 sample collected during Beijing’s severe winter haze in December 2016. Ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) was also applied to analyze the atomic compositions, the degree of unsaturation and the aromaticity of these samples. Both Type I and Type II photosensitized oxidation pathways were observed, which were postulated to be dictated by the packing density of the molecules at the air-water interface. These findings reveal that the photosensitization of HULIS at the air-water interface contributes greatly to the formation of atmospheric aerosols, further advancing our understanding of the important roles played by photosensitized chemistry in the atmosphere.
研究领域:
大气科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Jia Liu,Simin Ge,Peng Shao,Jianfeng Wang,Yanju Liu,Wei Wei,Can He,Lilan Zhang
The occurrence and removal rate of 52 typical pharmaceuticals and personal care products (PPCPs) were investigated in a wastewater treatment plant in Beijing, China. Thirty-three PPCPs were found in the influent, with caffeine (CF, 11387.0 ng L −1 ) being the most abundant, followed by N,N-diethyl- meta -toluamide (DEET, 9568.4 ng L −1 ), metoprolol (MTP, 930.2 ng L −1 ), and diclofenac (DF, 710.3 ng L −1 ). After treatment processes, the cumulative concentration of PPCPs decreased from 2.54 × 10 4 ng L −1 to 1.44 × 10 3 ng L −1 , with the overall removal efficiency (RE) of 94.3%. Different treatment processes showed varying contributions in removing PPCPs. PPCPs were efficiently removed in sedimentation, anoxic, and ultraviolet units. For individual compounds, a great variation in RE (52.1–100%) was observed. Twenty-two PPCPs were removed by more than 90%. The highly detected PPCPs in the influent were almost completely removed. Aerated grit chamber removed nearly 50% of fluoroquinolone (FQs) and more than 60% of sulfonamides. Most PPCPs showed low or negative removals during anaerobic treatment , except for CF which was eliminated by 64.9%. Anoxic treatment demonstrated positive removals for most PPCPs, with the exceptions of DF, MTP, bisoprolol, carbamazepine (CBZ), and sibutramine. DEET and bezafibrate were efficiently removed during the secondary sedimentation. Denitrification biological filter and membrane filtration also showed positive effect on most PPCPs removals. The remaining compounds were oxidized by 16–100% in ozonation . DF, sulpiride, ofloxacin (OFL), trimethoprim, and phenolphthalein were not amenable to ultraviolet. After the treatment, the residue OFL, CBZ, and CF in receiving water were identified to pose high risk to aquatic organisms. Considering the complex mixtures emitted into the environment, therapeutic groups psychotropics, stimulant, and FQs were classified as high risk. These findings provide valuable insights into adopting appropriate measures for more efficient PPCPs removals, and emphasize the importance of continued monitoring specific PPCPs and mixtures thereof to safeguard the ecosystem.
研究领域:
环境科学
·
污染控制
·
生态毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2019
·
IF 3.579
Xin Zhang,Peng Wang,Dandan Xu,Wenping Wang,Yan Zhao
Beijing rice vinegar is a typically traditional Chinese cereal vinegar and prevalent in the northern part of China. In this study, the volatile aroma analysis of different fermentation stages of Beijing rice vinegar was carried out by headspace-solid phase micro-extraction coupled with gas chromatography mass spectrometry (HS-SPME-GC-MS). The aroma could be classified into acids, alcohols, esters, aldehydes, ketones, polyphenols and heterocyclic compounds. The aroma constituents varied at each fermentation stage. Principle component analysis (PCA) was employed to distinguish the specific aroma compounds. At the alcoholization stage, alcohols were mainly ethanol (1993.10 μg/100 mL, 70%), and phenyl-ethyl alcohol (588.64 μg/100 mL, 20%). The ethyl ester meanwhile started to be produced and was the most prevalent ester. The high contents of ethanol, 3-methyl-butanol and phenyl-ethyl alcohol could be the potential aroma biomarker for the alcoholization stage. At the vinegarization stage, ethanol was largely consumed, as well as i-butanol and i-amyl alcohol. The concentration of volatile acids was 1948.01 μg/100 mL with acetic acid the most dominant one (> 90%). Acetic acid and 3-hydroxy-2-butanone were representative compounds for vinegarization stage and could be the potential biomarkers. Furthermore, the aroma comparison of 7 kinds of classic cereal vinegars was carried out. PCA results indicated that the specification of aroma biomarkers for each type of vinegar was practical, serving as the indicators or predictors for both the vinegar fermentation stage identification, vinegar sensory evaluation, and offering a potential for vinegar identification and quality improvement. The assessment strategy was also used to compare the typical Chinese and other important western vinegars.
研究领域:
食品科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2018
·
IF 3.412
Jia Huang,Yuping Liu,Wenxi Yang,Yingqiao Liu,Yu Zhang,Mingquan Huang,Baoguo Sun
Beijing douzhi (BD) is a traditional snack in Beijing, China, and it has been listed as a part of Beijing’s intangible cultural heritage. The potent odorants that contribute to the characteristic aroma of BD were investigated by analyzing the isolates from solvent-assisted flavor evaporation (SAFE) and simultaneous distillation–extraction. Using aroma extract dilution analysis based on gas chromatography–mass spectrometry and gas chromatography-olfactometry, 31 aroma-active compounds with flavor dilution (FD) factors ranging from 1 to 2187 were identified by comparison of their odor characteristics, MS data, and retention indices with those of reference compounds. To further determine their contribution to the aroma of BD, the odorants isolated using SAFE with FD factors ≥9 were quantified, and their odor activity values (OAVs; ratio of concentration to the respective odor threshold in water) were calculated. Eleven compounds were found to have OAVs ≥ 1, which indicated they were the potent odorants that contributed substantially to the characteristic aroma of BD. Among the 11 odorants, (E,Z)-2,6-nonadienal, eugenol, methional, p-cresol, 1-octen-3-one, and 3-methylbutanoic acid were not previously identified in BD.
研究领域:
食品科学
·
分析化学
·
香料化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）