Determination of methyl tert-butyl ether (MTBE) in Chinese fuels by gas chromatography/mass spectrometry and gas chromatography/flame ionization detector

A method was developed to determine the concentration of methyl tert-butyl ether(MTBE) in gasoline,diesel and heating oil by gas chromatography(GC) with mass spectrometry(GC-MS) or flame ionization detection(FID). The diluted gasoline was directly injected into the GC, and the complete separation of MTBE from co-eluting hydrocarbons was not required. GC/MS or GC/FID method can be used to analyze MTBE in different concentration range and have good consistency.     

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.     

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.     

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。     

小体积液液萃取-GC/MS法测定地表水中有机磷农药

采用小体积液液萃取-气相色谱/质谱联用法测定地表水中有机磷农药,以1.2 mL正己烷为萃取剂,磷酸三苯酯为内标,对8种目标化合物的富集倍数达156～436.方法在1.00 μg/L～20.0 μg/L范围内线性良好,8种有机磷农药的检出限均为0.2 μg/L,实际水样平行测定的RSD为2.1%～9.7%,平均加标回收率...     

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...     

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....     

Altitude profiles of total chlorinated paraffins in humus and spruce needles from the Alps (MONARPOP)

Chlorinated paraffins (CPs) are toxic, bioaccumulative, persistent, and ubiquitously present in the environment. CPs were analyzed in humus and needle samples, which were taken within the Monitoring Network in the Alpine Region for Persistent and other Organic Pollutants (MONARPOP) at sampling sites of 7 different altitude profiles in the Alps. Gas chromatography combined with electron ionization tandem mass spectrometry (EI-MS/MS) was used for the determination of total CPs (sum of short, medium and long chain CPs). CPs were found in all samples; the concentrations varied between 7 and 199 ng g⁻¹ dry weight (dw) and within 26 and 460 ng g⁻¹ dw in humus and needle samples, respectively. A clear vertical tendency within the individual altitude profiles could not be ascertained. Within all altitude profiles, elevated concentrations were observed in humus samples taken between 700 and 900 m and between 1300 and 1500 m. In the needle samples no similar correlation could be observed due to higher variation of the data.