Characterization of fine organic particulate matter from Chinese cooking

PM2.5 samples were collected by a three-stage cascade impactor at two kinds of Chinese restaurants to characterize fine organic particulate matter from Chinese cooking sources. Major individual organic compounds have been quantified by GC/MS, including series of alkanes, n-alkanoic acids, n-alkanals, alkan-2-0nes and PAHs.Alkanes and ketones make up a significant fraction of particle-phase organic compounds, ranging from C11 to C26,and (C9 to C19, respectively. In addition, other organic compound classes have been identified, such as alkanols,esters, furans, lactones, amides, and nitriles. The mass concentrations of fine particles, alkanes, n-alkanoic acids and PAHs in air emitted from the Uigur style cooking are hundreds times higher than ambient PM2.5in Beijing.     

苏玛罐采样-GC-FID/MS同时测定环境空气中多种VOCs

采用苏玛罐采样-大气预浓缩仪结合气相冷柱箱与Deans Switch中心切割技术,将C2～C3组分切割至HP-PLOT/Q+PT柱,用FID检测器分析,其余组分通过DB-1柱子分离后进入质谱分析,实现1次进样同时测定环境空气中57种PAMS和65种TO-15.结果表明:108种VOCs在0.15 nmol/mol～8....     

Determination of polycyclic aromatic hydrocarbons and substitutes (Nitro-, Oxy-PAHs) in urban soil and airborne particulate by GC-MS and NCI-MS/MS

A method involving high resolution gas chromatography combined with ion trap (HRGC-MS/MS) and negative chemical ionisation (NCI) was developed for the determination of nitrated or oxygenated polycyclic aromatic hydrocarbons (nitro-PAHs, oxy-PAHs) and other electrophilic substitutes in soil samples. Efficient clean-up was achieved by a combination of methods for the determination of PAHs in soil and nitro-PAHs in aerosol using solid phase extraction (SPE) and semipreparative high performance liquid chromatography (HPLC). In samples of surface soil from the city of Basle (Switzerland), nitro-PAHs (mainly 3-nitrofluoranthene and 1-nitropyrene) were found in concentrations between 30 and 800 ng/kg dry weight. Oxy-PAHs and parent PAHs revealed 10²-10⁴-fold higher levels. Nitro-PAHs which are up to 10⁵ times more mutagenic seem to be less persistent in soil than the parent forms, although their entire mutagenic potential has to be estimated as being on the same order of magnitude. In urban air particulate matter, the amounts of nitro-PAHs (2–62 pg/m³) were 10–100 times lower than oxyPAHs and parent PAHs which were both found in a similar range. 3-nitrobenzanthrone, a recently described suspected human carcinogen has not yet been detected. Using multivariate statistical analysis, it was possible to elucidate similarities or special characteristics of substances in a given matrix reflecting their chemical properties or specific emission sources.     

基于分散固相萃取-超高效液相色谱串联质谱法测定沉积物中大环内酯类抗生素

采用分散固相萃取与超高效液相色谱串联质谱技术,建立了快速测定沉积物中9种大环内酯类抗生素(螺旋霉素、阿奇霉素、替米考星、竹桃霉素、红霉素、泰乐菌素、吉他霉素、罗红霉素和交沙霉素)的检测方法.沉积物经磷酸盐缓冲液和乙腈混合液浸提,再经过石墨化炭黑和C18硅胶分散固相萃取材料净化.采用超高效液相色谱串联质谱仪(UPLC-M...     

Evaluation of the impact of matrix effects in LC/MS measurement on the accurate quantification of neonicotinoid pesticides in food by isotope-dilution mass spectrometry

The use of isotope-labeled internal standards is the most widely accepted approach to overcome the matrix effects on quantification of pesticides in food by LC/MS. We evaluated the impact of the matrix effects on quantification of six neonicotinoid pesticides, acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam, in food by using deuterated internal standards. The calibration curves for each pesticide were obtained by using matrix-free and matrix-matched calibration solutions with blank brown rice, carrot, and green onion extracts. For brown rice and carrot, the matrix effects were not observed. In contrast, the slopes of calibration curves for each pesticide were influenced by presence of green onion extracts in calibration solutions (variability of the slopes was 4–9%), because the ratios of peak area for native pesticide to those for internal standards were influenced by matrix. The spike-and-recovery test with green onion was also performed. The analytical values obtained by using matrix-free calibration solution were biased from the spiked concentration, whereas those obtained by using matrix-matched calibration solution were comparable to the spiked concentration. These results indicate that matrix-matched calibration solution should be used for accurate quantification of neonicotinoid pesticides in food by LC/MS using deuterated internal standards.     

Ultra trace simultaneous determination of 50 polycyclic aromatic hydrocarbons in biota using pMRM GC-MS/MS

Abstract

A saponification extraction method with gas chromatography pseudo-MRM (pMRM) mass spectrometry detection was developed for the determination of 50 total polycyclic aromatic hydrocarbons (TPAH50, a combination of parent and alkylated homologues) in biota. The method was aimed at monitoring and identification of potential TPAH contaminants in bitumen impacted environments. Alkylated PAHs were determined by multi-level, quantitative calibration using parent PAHs. The developed and thoroughly validated method required only one injection for TPAH50 analysis which represents significant saving of time and expensive authentic alkylated standards. The current method was tested with certified reference mussel tissue NIST 1974c and performed well. In a comparison study, the method reached a limit of quantitation (LOQ) for the TPAH50 between 0.1 and 0.2?ng g^?1, while the QuEChERs enhanced matrix removal – lipid (EMR) kit produced by Agilent showed an LOQ of 5–10?ng g^?1. The current method relied on response factors (RF) for the quantitation of alkylated PAHs determined against parent PAHs. These RFs were shown to be stable and consistent over the course of 1 year, during which over 200 routine environmental biota monitoring samples were analyzed. The environmental biota monitoring samples analyzed include muscle, carcass and liver, with an average total PAH50 concentration of 13, 90 and 135?ng g^?1, respectively. Results show significant differences in the distributions of 1 ringed, 2 ringed, 3 ringed, 4 ringed, and 5+ ringed TPAHs between the types of biota samples.     

PDE accident model from a safety information perspective and its application to Zhangjiakou fire and explosion accident

Accident models can provide theoretical frameworks for determining the causes and mechanisms of accidents, and thus are theoretical bases for accident analysis and prevention. The role of safety information in accident causation is profound. Thus, safety information is an important and essential perspective for developing accident models. This study presents a new accident model developed from a safety information perspective, called the Prediction—Decision—Execution (PDE) accident model. Because the PDE accident model is an emerging accident model that was proposed in 2018, its analysis logic and viability remain to be discussed. Thus, the main contributions of this study include two aspects: (i) detailed explanation of the analysis logic of the PDE accident model, and (ii) case-study examination of the Zhangjiakou fire and explosion accident, a serious accident that occurred in China in 2018, to demonstrate the viability of the PDE accident model. Results show that this is a safety-information-driven accident model that can provide a new and effective methodology for accident analysis and prevention, and safety management.     

基质固相分散-快速溶剂萃取-GC/MS法同时测定土壤中有机氯农药和多环芳烃

建立了基质固相分散-ASE提取-GC/MS法同时测定土壤中8种有机氯农药和16种多环芳烃的方法。对方法的线性、检出限、精密度、回收率及土壤质控样品进行了分析,结果表明,8种有机氯农药和16种多环芳烃线性良好,相关系数为0.997 5～0.999 8,方法检出限为0.39～1.57μg/kg,空白加标样品的相对标准偏差小于20%,实际土壤样品加标回收率为60.6%～125%,土壤质控样品结果均在范围内。该方法能够满足土壤中8种有机氯农药和16种多环芳烃的检测要求。     

ICP-MS法测定地下水中痕量元素的条件选择

采用氦气碰撞模式和内标法抑制ICP-MS测试地下水中痕量元素的多原子离子干扰和基体效应。探讨He流量、内标元素、宏量离子等因素对测定的影响,结果表明:187Re、208Pb响应值与He流量呈线性下降模型,其他离子为指数下降模型,He流量为2. 5 m L/min～3. 0 m L/min时满足地下水质量分级测定要求;内标元素的响应因子随质量浓度的增大而降低,16. 0μg/L以上时趋于稳定;酸度显著影响测定误差,选用较大质量数的内标元素和保持样品酸度的一致可提高测定的准确度。     

Triclosan in Fresh Water Fish Gibelion Catla from the Kaveri River,India, and Its Consumption Risk Assessment

Triclosan is a common antimicrobial agent that is found in significant levels in the aquatic environment and may elicit effects on aquatic organisms through unexpected modes of action. In this study, triclosan was quantified in fish from the Kaveri River, India, by using the gas chromatography and mass spectrometry technique and it was found in the range of 0.73–50 ng/g wet weight (ww). The mean bioaccumulation factor based on water (BAF_w 820) and sediment (BAF_s 2.12) in the Kaveri River showed that triclosan is accumulative in fish, and reflects its feeding behavior. The bioaccumulation indicates triclosan's persistence or prevalence throughout the river stretch. Human risk assessment through dietary intake demonstrated that the triclosan exposure is five orders of magnitude lower than the acceptable daily intake (50 μg/kg bw) and US EPA reference dose (300 μg/kg bw/day). This investigation is the first to report the bioaccumulation of triclosan in freshwater fish from India. Further, the results indicate that this fish acts as a biomarker of exposure for triclosan and thus shall be used to report triclosan pollution in the future.