吹扫捕集-气相色谱/质谱法测定地表水中7种硝基苯类化合物

Determination of seven nitrobenzene compounds in surface water by purge and trap-gas chromatography/mass spectrometry

目的通过吹扫捕集-气相色谱/质谱仪(PT-GC/MS),建立地表水中7种硝基苯类化合物(硝基苯、邻-硝基甲苯、间-硝基甲苯、对-硝基甲苯、对-硝基氯苯、间-硝基氯苯和邻-硝基氯苯)的快速检测方法。方法采集500 ml地表水,滤纸过滤后,进样5 ml,7种硝基苯类化合物经吹扫捕集装置吸附富集、解吸后,采用DB-624(60 m×0.25 mm,0.14μm)毛细管色谱柱分离,用气相色谱-质谱联用仪测定,SIM模式检测,外标法定量。结果7种硝基苯类化合物的标准曲线范围均为5μg/L~25μg/L,以浓度为横坐标、定量离子峰面积为纵坐标生成标准曲线,相关性系数为0.9990~0.9993;检出限为0.03μg/L~0.06μg/L,定量限为0.1μg/L~0.2μg/L;对实际水样进行加标回收试验:加标浓度均为10.0μg/L时,加标回收率为92.2%~94.0%,相对标准偏差为1.0%~2.6%(n=6);加标浓度均为22.0μg/L时,加标回收率为96.8%~98.2%,相对标准偏差为1.3%~1.8%(n=6)。应用该方法对绍兴地区某河流中的硝基苯类化合物进行检测,7种化合物均未检出。结论该方法快速、简单、结果准确、重现性好,适用于地表水中痕量硝基苯类化合物的测定。

Objective This paper aims to establish a method for the fast determination of 7 nitrobenzene compounds including nitrobenzene,2-nitrotoluene,3-nitrotoluene,4-nitrotoluene,1-chloro-4-nitrobenzene,1-chloro-3-nitrobenzene,and 1-chloro-2-nitrobenzene in surface water by purge and trap-gas chromatography/mass spectrometry(PT-GC/MS).Methods A total of 500 ml surface water samples were collected and then filtrated with filter paper.5 ml water sample was in⁃jected into purge and trap device.Seven nitrobenzene compounds were adsorbed,concentrated and desorbed by purging and trapping device,separated by DB-624(60 m×0.25 mm,0.14μm)capillary column,determined by gas chromatograms/mass spectrometry in SIM mode,and quantified by external standard method.Results The standard curves of 7 nitrobenzene compounds ranged from 5μg/L to 25μg/L.The standard curves were generated with the concentration as the horizontal coordi⁃nate and the quantitative ion peak area as the vertical coordinate,and the correlation coefficients(r)were within 0.9990-0.9993.The limits of detection were from 0.03μg/L to 0.06μg/L,and the limits of quantification were from 0.1μg/L to 0.2μg/L.The recoveries were within 92.2%-94.0%and the relative standard deviations were within 1.0%-2.6%(n=6)when the concentration was 10.0μg/L.The recoveries were within 96.8%-98.2%and the relative standard deviations were within 1.3%-1.8%(n=6)when all the concentrations were 22.0μg/L.The method was used to detect nitrobenzene compounds in a river in Shaoxing area,but none of the 7 compounds was detected.Conclusion The method is rapid,simple,accurate and reproducible,which is suitable for the analysis of 7 nitrobenzene compounds in surface water.