固相萃取-在线凝胶渗透色谱-气相色谱-串联质谱法测定水中31种有机氯农药

Determination of 31Organochlorine Pesticides in Water by SPE-Online GPC-GC-MS/M S

建立了固相萃取(SPE)-在线凝胶渗透色谱(GPC)-气相色谱-串联质谱法(GC-MS/M S)测定水中31种有机氯农药(OCPs)含量的方法,并用于福建各地水样的分析。水样以10mL·min^(-1)速率过SPE柱,吹氮10min除去水分,用5mL二氯甲烷以1.0mL·min^(-1)速率过柱洗脱目标物,样品瓶隔夜沥干,用5mL二氯甲烷分2次洗涤,洗涤液合并至洗脱液中,吹氮至0.5mL,供在线GPC净化和GC-MS/M S分析。在线GPC净化中采用GLNpak EV-200色谱柱和体积比为3∶7的丙酮-环己烷混合液;气相色谱以SH-Rxi-5Sil MS型毛细管色谱柱为固定相,在程序升温下进行色谱分离;串联质谱以电子轰击离子(EI)源电离,在多反应监测模式下检测;以基质匹配混合标准溶液系列制作工作曲线,外标法定量。结果显示:水中31种OCPs的质量浓度和其对应的峰面积均在一定范围内呈线性关系,检出限为0.3~8.3ng·L^(-1)。对实际水样进行3个浓度水平的加标回收试验,31种OCPs的回收率为67.0%~123%,测定值的相对标准偏差(n=6)为3.9%~20%。用此方法分析福建省11个地区枯水期的水样(包括海水、地表水和工业废水),结果显示:福建省枯水期各水体中OCPs的检出量为5.2~125.6ng·L^(-1),宁德三都澳(海水)检出OCPs的种类较多(11种),与福建省2006年以前文献报道的数据相比,OCPs检出量较低,且均低于中国或权威组织机构标准规定的限值。

A method was developed for the determination of 31OCPs in water by SPE-online GPC-GC-MS/MS,and applied to the analysis of water samples from different regions in Fujian province.Water sample was introduced into SPE column at the rate of 10mL·min^(-1),then the column was blown for 10min with nitrogen to remove the water.Then 5mL of dichloromethane was used to elute analytes at the rate of 1.0mL·min^(-1).Sample bottles were drained overnight,and washed twice with 5 mL of dichloromethane.The washing solution was combined with the eluate,then the mixture was blown to 0.5 mL with nitrogen,purified by online GPC and analyzed with GC-MS/MS.In online GPC analysis,GLNpak EV-200column and mixed solvent composed of acetone and cyclohexane with volume ratio of 3∶7were used.In GC analysis,SH-Rxi-5Sil MS capillary chromatographic column was used as stationary phase under temperature programmed condition.In MS/MS analysis,EI was used to deionize and MRM mode was used to detect.Working curves were made by using matrix matching mixed standard solution series,and external standard method was used for quantification.Linearity relationships between mass concentrations of 31OCPs and their respective peak areas were all kept in definite ranges,with detection limits in the range of 0.3-8.3ng·L^(-1).The spiked recovery test was made on actual water samples at 3concentration levels,giving recoveries in the range of 67.0%-123%,and RSDs(n=6)of determined values ranged from 3.9%to 20%.The proposed method was used in analyzing water samples(including sea water,surface water and industrial wastewater)during the dry season from 11regions of Fujian province,and the results showed that the detected amount of OCPs in water body was in the range of 5.2-125.6ng·L^(-1),and more OCPs(11species)w ere detected in the seawater of Sandu′ao in Ningde.The detected amount of OCPs was lower than the previous data in Fujian Province,all lower than the limit specified by the standards from ching or authoritative organization.