Improvement of an efficient separation method for chemicals in diesel exhaust particles: analysis for nitrophenols

GOAL, SCOPE, AND BACKGROUND: Diesel exhaust is believed to consist of thousands of organic constituents and is a major cause of urban pollution. We recently reported that a systematic separation procedure involving successive solvent extractions, followed by repeated column chromatography, resulted in the isolation of vasodilatory active nitrophenols. These findings indicated that the estimation of the amount of nitrophenols in the environment is important to evaluate their effect on human health. The isolation procedure, however, involved successive solvent extractions followed by tedious, repeated chromatography, resulting in poor fractionation and in a significant loss of accuracy and reliability. Therefore, it was crucial to develop an alternative, efficient, and reliable analytical method. Here, we describe a facile and efficient acid-base extraction procedure for the analysis of nitrophenols. MATERIALS AND METHODS: Diesel exhaust particles (DEP) were collected from the exhaust of a 4JB1-type engine (ISUZU Automobile Co., Tokyo, Japan). Gas chromatography-mass spectrometry (GC-MS) analysis was performed with a GCMS-QP2010 instrument (Shimadzu, Kyoto, Japan). RESULTS: A solution of DEP in 1-butanol was extracted with aqueous NaOH to afford a nitrophenol-rich oily extract. The resulting oil was methylated with trimethylsilyldiazomethane and subsequently subjected to GC-MS analysis, revealing that 4-nitrophenol, 3-methyl-4-nitrophenol, 2-methyl-4-nitrophenol, and 4-nitro-3-phenylphenol were present in significantly higher concentrations than those reported previously. DISCUSSION: Simple acid-base extraction followed by the direct analysis of the resulting extract by GC-MS gave only broad peaks of nitrophenols with a poor detection limit, while the GC-MS analysis of the sample pretreated with (trimethylsilyl)diazomethane gave satisfactorily clear chromatograms with sharp peaks and with a significantly lowered detection limit (0.5 ng/ml, approximately 100 times). CONCLUSION: The present method involving an acid-base extraction, in situ derivatization, and GC-MS analysis has shown to be a simple, efficient, and reliable method for the isolation and identification of the chemical substances in DEP.     

便携式GC-MS法快速测定固定污染源废气中的VOCs

采用便携式GC-MS法快速测定固定污染源废气中VOCs,32种VOCs在2×10~(-7)~1×10~(-6)范围内线性良好,方法检出限为2×10~(-9)~1×10~(-8),标准气体样品6次测定结果的RSD为1.9%~19.1%,环境空气样品的加标回收率为66.2%~116%。在实际现场监测固定污染源中VOCs时,使用速查(Survey)功能可初步判断样品浓度,确定稀释倍数。比对试验结果表明,气袋和玻璃注射器采样法对VOCs测定结果无显著性差异。     

投菌生物接触氧化法处理洁霉素废水的机理研究

研究了“水解酸化－二段生物接触氧化－混凝”工艺处理高浓度洁霉素废水处理系统中好氧微生物膜特性,分布规律、降解作用,高效降解菌的选育,投加菌在反应器中能否保持优势等问题,以探讨用投菌生物接触氧化法处理洁霉素废水的机理,对本系统好氧微生物膜进行后仍存于反应器中并占有优势,最优势菌株经鉴定属气单胞菌属、通过对中试好氧处理出水进行定性定量分析,寻找其引起剩余ＣＯＤｃｒ值的原因。     

固相萃取-气质联用法测定固体废物浸出液中的二硝基苯

建立了一种利用固相萃取法对固体废物浸出液(TCLP)中二硝基苯进行萃取,DB-5石英毛细管柱(30 m×0.25 mm×0.25μm)进行分离,质谱检测器检测二硝基苯的方法。方法在0.002 0~0.020 0 mg/L之间线性关系良好,二硝基苯三种同分异构体的检出限均为0.5μg/L,模拟样品加标回收率为93%~96%,RSD≤2%;实际固体废物样品测定的加标回收率为95%~98%。     

环境中二噁(口英)及其检测技术进展

从二(?)(?)类化合物的结构、来源、毒性等简要说明对其监测的必要性,且从仪器监测(包括气相色谱、气质联用、串联质谱等)和生物监测(包括利用指示生物、生物标志物等)概述了80年代以来国内外对二(?)(?)类物质尤其是几种极毒性化合物如多氯代二苯二(?)(?)(PCDDs)和多氯代二苯呋喃(PCDFs)等化合物的检测技术成果。     

加速溶剂萃取-气相色谱/串联质谱法测定土壤中20种有机氯农药

建立了用加速溶剂萃取法（ASE）提取、气相色谱-串联质谱法分析土壤中20种有机氯农药的方法。用正己烷和丙酮（1∶1,V/V）的混合溶剂为提取剂,萃取温度100℃,压力1 500 psi,静态提取10 min,循环提取2次,提取液经石墨化碳黑固相萃取柱净化,浓缩后进行GC-MS/MS测定,外标法定量。试验结果表明,采用串联质谱多反应监测模式,降低了背景干扰,当取5 g土壤时,有机氯农药的检出限在0.1~3.0μg/kg之间,低浓度水平（8μg/kg）的基体加标回收率为70.3%~134%,相对标准偏差〈23%。测定方法背景干扰低,灵敏度高,适合土壤中20种有机氯农药残留的同时测定。     

超声波提取-GC/MS法测定生物体内硝基苯类化合物

以洪泽湖中6种代表性生物为研究对象,采用超声波法提取样品中硝基苯类化合物,用凝胶色谱净化、浓缩,气相色谱／质谱联用法测定。该法与索氏提取法在同等试验条件下进行加标回收试验,前者回收率高且稳定,简便可行。方法检出限为0．008μg／g～0．030μg／g,平均加标回收率为76．5％～109％,重复测定3次的RSD为1．5％～13．0％。     

利用MALDI-TOF MS技术简便、快速检测水华蓝藻的方法研究

以水华蓝藻为研究对象,用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)技术对其进行测定分析并获得了蛋白质指纹图谱。对铜绿微囊藻标准株(NIES-843)样品通过3种前处理方法得到的质谱图进行对比,确定了质谱分析的样品前处理方法,建立了利用MALDI-TOF MS技术简便、快速检测水华蓝藻的方法。对在水华中出现的4种不同蓝藻进行MALDI-TOF MS分析,结果表明各种蓝藻具有其特征性波谱,可据此对水华蓝藻进行区分和鉴定。该方法快速、简便、精确、可程序化,具有广泛的应用前景。     

气相色谱—串联质谱法检测水中苯霜灵、甲霜灵、噁霜灵残留量

建立水中甲霜灵、苯霜灵、噁霜灵农药残留量的气相色谱—串联质谱(GC-MS/MS)的检测分析方法。样品采用乙腈提取、固相萃取(SPE)柱净化。采用GC-MS/MS分析时,三种农药在15 mim内完全分离并流出。添加浓度加标回收率为80.6%~88.4%,相对标准偏差(RSD)小于5.0%。在0.01~0.20 mg/L质量浓度范围之间线性关系良好(r~20.999 0)。该方法的灵敏度、精密度和准确度均满足农药残留分析要求,适用于水中的农药残留的快速筛查与定性、定量分析。     

工业废水对洹河有机污染的调查与分析

采用适当的样品前处理技术,利用GC/MS对洹河水及焦化厂、染料厂废水进行有机污染物的分析,确定了工业废水对洹河造成有机污染的主要化合物,从而为企业污水的处理和洹河治理提供依据.