顶空固相微萃取/气相色谱-三重四极杆串联质谱法测定地表水与饮用水中的挥发性有机物

Determination of Volatile Organic Compounds in Surface Water and Drinking Water by Gas Chromatography-Triple Quadrupole Tandem Mass Spectrometry with Head Space-Solid Phase Microextraction

采用部分因子试验设计筛选出顶空固相微萃取的主要影响参数,利用中心复合设计对主要影响参数的取值进行了优化,建立了顶空固相微萃取(HS-SPME)结合气相色谱-三重四极杆串联质谱(GC-MS/MS)测定地表水和饮用水中55种挥发性有机物(VOCs)的分析方法。取5.0 mL样品于顶空瓶中,加入0.75g NaCl,使用CAR/PDMS 75μm纤维头,萃取温度40℃,萃取时间40 min,解析温度300℃,在GC-MS/MS选择反应监测(SRM)模式下检测,内标法定量。结果表明,55种VOCs在0.04~0.40、0.4~4.0、4.0~100μg/L质量浓度范围内线性良好,相关系数(r^2)均大于0.99,方法的检出限为0.03~80 ng/L,定量下限为0.1~300 ng/L。55种VOCs在0.2、2.0、40μg/L 3个加标水平下的平均回收率为77.3%~124%,相对标准偏差(RSD,n=6)为1.3%~17%。对3种地表水和3种饮用水进行测定,地表水中有37种VOCs被检出,饮用水中有25种VOCs被检出。实验证明,建立的HS-SPME和GC-MS/MS相结合的检测方法具有准确可靠、简单快速、灵敏度高等优点,适用于地表水和饮用水中VOCs的同时测定。

A method was established for the simultaneous determination of volatile organic compounds(VOCs)in surface water and drinking water by gas chromatography-triple quadrupole tandem mass spectrometry(GC-MS/MS)with head space-solid phase microextraction(HS-SPME).The performance of the five fibers was tested in univariate mode whereas the other variables affecting the efficiency of SPME analysis were optimized by factorial design and central composite design.The optimal SPME extraction conditions were as follows:75μm of carboxen/polydimethylsiloxane fiber,5 mL of sample volume,40 min of extraction time,40℃of extraction temperature,300℃of desorption temperature,and 15.0%of NaCl.The analytes were determined by GC-MS/MS in selected reaction monitoring(SRM)mode,and the VOCs were quantified by internal standard method.Results showed that there were good linear relationships for 55 VOCs in the ranges of 0.04-0.4μg/L,0.4-4.0μg/L and 4.0-100μg/L,respectively,with correlation coefficients(r 2)all larger than 0.99.The limits of detection(LODs)and limits of quantification(LOQs)were in the range of 0.03-80 ng/L and 0.1-300 ng/L,respectively.Recoveries at three spiked levels of 0.2,2.0 and 40μg/L ranged from 77.3%to 124%with relative standard deviations(RSDs,n=6)renged from 1.3%to 17%.The developed method was applied in the determination of VOCs in surface water and drinking water,in which 37 VOCs and 25 VOCs were detected,respectively.The method is accurate,reliable,simple,rapid and sensitive,and is suitable for the simultaneous detection of VOCs in surface water and drinking water.