火灾中聚合物材料热解对汽油辨识的影响分析

火灾中聚合物材料的燃烧过程产生的热解产物,从而增加化学分析谱图的复杂性,对助燃剂鉴定造成干扰。针对常见的聚合物材料开展了一系列燃烧实验,对其在燃烧过程中的热解机理进行了分析,并通过汽油存在条件下的聚合物材料燃烧实验分析了热解对汽油辨识产生的干扰。     

Volatile components and their corresponding synthetic gene expression profile in the fruits of Actinidia chinensis北大核心CSCD

This study aimed to identify the difference in volatile aromatic components and the relationship with the expression pattern of their corresponding bio-synthesis genes in six kiwifruit (Actinidia chinensis) varieties (Cuiyu, Jintao, Jinyan, Chuhong, Donghong, and Xixuan). To provide a foundation for kiwifruit variety recognition, fruit quality evaluation, and molecular-assisted breeding, the volatile aromatic components in the ripe fruits of six kiwifruit varieties were evaluated by head space-solid phase micro extraction/gas chromatography-mass spectrometry. The aroma-synthesis-related genes, including acyltransferases (AcAT16), lipoxygenase (AcLox2), and terpene synthase genes (AcTPS1), were detected by the real time-quantitative polymerase chain reaction (qPCR) during the postharvest stage of fruits. Ninety-two aroma chemicals were identified in the tested kiwifruit cultivars. There were 35, 32, 30, 44, 28, and 17 of aromatic compounds in Cuiyu, Jintao, Jinyan, Chuhong, Donghong, and Xixuan, respectively. Esters were the main aroma components in Cuiyu, Jintao, and Jinyan. The major aromatic compounds of Chuhong, Donghong, and Xixuan were aldehydes and terpenoids. The expression level of AcATs16 and AcLox2 increased, and then decreased during the ripening of kiwifruit fruits. The expression of AcATs16 was significantly higher in Cuiyu and Jinyan than in other varieties. AcLox2 indicated significant abundance in Cuiyu and Chuhong. AcTPS1 was up-regulated in Jintao, Donghong, and Xixuan with fruit ripening; however, this was not observed in Cuiyu, Chuhong, and Jinyan. The difference in the composition and content of volatile aromatic components contributes to the difference in aroma in different kiwifruit cultivars. The diverse expression of AcATs16, AcLox2, and AcTPS1 might be closely related to the synthesis of ethyl butyrate, (E)-2-hexenal, and eucalyptol, respectively. © 2018 Science Press. All rights reserved.     

土壤中苯系物的吹扫捕集-气相色谱-质谱测定方法

采用吹扫捕集-气相色谱-质谱联用(PT-GC-MS)法,研究了污染土壤中苯系物(包括苯、甲苯、乙苯、对间二甲苯、邻二甲苯和异丙苯)的测定方法,优化了吹扫捕集作为北京潮土中苯系物预处理方法的参数. 结果表明,吹扫时间11 min,解吸温度190 ℃和解吸时间0.5 min为最佳的吹扫捕集方法参数. 采用PT-GC-MS法测定土壤中的苯系物的平均加标回收率为99.0%～103.9%,相对标准偏差为10.3%～17.5%(n=7);苯系物的检出限为1.6～2.8 μg/kg,定量限为5.4～9.6 μg/kg. 将研究结果与文献中的苯系物监测质量控制参数进行比较发现,由于采用有机质含量低、砂质壤土质地的北京潮土为研究对象,使该试验的回收率均高于文献中的结果;同时,相对标准偏差和检出限与文献中的结果也存在差异,主要是由于挥发性污染物所赋存的介质及实验仪器操作条件不同所致.      

应急监测中便携式顶空/GC-MS法测定水中VOCs的初步研究

通过对实验室加标水样和实际水样的测定,研究了便携式顶空/气相色谱-质谱法(GC-MS)与吹扫捕集/GC-MS法测定水中VOCs的性能比较,探讨了利用Loop环测定水中高浓度VOCs的准确度. 结果表明:便携式顶空/GC-MS测定水中54种低浓度VOCs的检出限略高于吹扫捕集/GC-MS系统,准确度和精密度分别为67.4%～136%和9.08%～19.80%,均满足环境应急监测分析的要求;利用Loop环,便携式顶空/GC-MS可对水中高浓度级(mg/L)VOCs进行较为准确地测定,回收率为100%～149%;复杂的实际样品基本不干扰便携式顶空/GC-MS的测定,与吹扫捕集/GC-MS法相比,二者对实际水样的测定结果相对偏差小于20%;便携式顶空/GC-MS在水污染事故现场可得到基本准确的结果,可为事故后续处理提供有效的数据支持.      

胶州湾某水域蛤蜊(Ruditapes philippinarum)、牡蛎(Crassostrea ariakensis)中的雌激素含量

为了探讨海洋贝类对环境中雌激素的富集情况,采用液-液萃取和固相萃取方法提取了胶州湾李村河入海口蛤蜊、牡蛎和底泥中的雌酮(E1)、雌二醇(E2)、雌三醇(E3)和雌炔醇(EE2),并用GC-MS方法测定了上述4种物质的含量,此外还采用暴露实验方法研究了蛤蜊吸收底泥中雌激素物质的影响因素.测定结果显示,该水域中蛤蜊全组织中E1含量为0.45～5.20ng·g-1,E2含量为nd～4.34ng·g-1,E3和EE2未检出;牡蛎体内的E1、E2和E3含量分别为4.64～29.66、2.16～7.20和0.96～7.96ng·g-1,EE2未检出;底泥中E1、E2和E3含量分别为0.43～2.36、nd～0.59、0.52～1.13ng·g-1,EE2未检出.蛤蜊和牡蛎体内的雌激素物质含量高于其栖息的底泥.暴露实验结果显示,随着底泥中雌激素物质含量的增加或暴露时间增加,蛤蜊体内雌激素物质的含量增加,贝类可吸收并富集底泥中的雌激素物质.     

滩涂及贝类中残留三唑磷的GC/MS分析

建立了滩涂和贝类中残留有机磷类农药三唑磷的毛细管气相色谱-质谱联用检测法。向冷冻干燥后的样品中加入邻苯二甲酸二戊酯作为定量内标物,用乙酸乙酯:正己烷(体积分数1:1)提取,浓缩定容后用EI源在SIM检测模式下进行检测。结果表明,三唑磷与内标物在SBP-50柱上得到良好的分离,色谱峰尖锐,没有杂峰干扰。在(2.50~50.00)ng/mL浓度范围内具有良好的线性关系,线性方程为y=8.261×10-4x,相关系数为0.999 8。方法的最低检测限0.18×10-9。平均回收率为90.96％~102.15％,相对标准偏差为3.81％~4.82％。对采自浙江沿海7个采样点沉积物和三种海产贝类进行了测定,三唑磷含量在(0-1.31)×10-6范围内。     

便携式布氏硬度计在电厂金属硬度检测中的应用

针对电厂金属部件及焊缝现场硬度检测中里氏硬度计误差较大的问题,介绍了有关标准的进展情况,以及便携式布氏硬度计和压痕自动测量装置的最新技术.结果表明:在现场硬度检测中,对有争议的硬度值宜采用便携式布氏硬度计进行测量校核,国内已形成关于便携式布氏硬度计的标准体系,自动压痕测量装置配合便携式布氏硬度计非常适于电厂的现场硬度检测,通过换算得到的数据,不能作为投诉和满足验收要求的依据.     

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.     

分散液液微萃取气相色谱-质谱法测定水中15种硝基苯类化合物

建立了超声辅助基质分散液液微萃取（UA-DLLME）作为前处理联合气相色谱串联质谱（GC-MS）同时测定地下水和地表水中15种硝基苯类化合物的分析方法。萃取剂、分散剂、萃取温度、萃取时间和离子强度等影响因素采用Plackett-Burman设计,快速筛选出最显著影响因素,利用中心组合设计（CCD）简化实验步骤优化显著因素,结合响应曲面图最终确定最佳的萃取条件：5 mL水样在3%氯化钠条件下迅速加入40 μL四氯化碳（萃取剂）和0.5 mL乙腈（分散剂）,50 ℃下超声4 min,混合液4 000 r/min离心3 min。结果表明：15种硝基苯类化合物在50.0~1 000.0 μg/L的浓度范围内线性相关系数均大于0.995;采用超声辅助基质分散液液微萃取时,方法检出限（MDL）为0.018~0.039 μg/L;15种目标物的加标平均回收率为83.31%~99.08%,相对标准偏差均不高于5.0%（n=6）。     

水中佳乐麝香的固相微萃取-气质联机测定方法

采用聚二甲基硅氧烷膜厚100μm的纤维萃取设备,阐述了测定水中HHCB的固相微萃取-气质联机的检测方法。研究发现,对于水中的HHCB来说,温度控制在35℃,萃取时间为40 min,pH值为7.0,可实现HHCB的有效萃取,水中的离子对萃取效率的干扰较小。使用该方法测得上海龙华污水厂原水中HHCB浓度为286 ng/L,虹口区泗塘河水中HHCB浓度低于检测下限。