气相-动态顶空进样-气相色谱/质谱法间接测定饮用水源水中苦味酸

Indirect determination of picric acid in drinking source water by D-HS-GC/MS Method

建立气相-动态顶空进样-气相色谱/质谱法（D-HS-GC/MS）间接测定饮用水源水中苦味酸（即2,4,6-三硝基苯酚）的方法。基于苦味酸与次氯酸钠反应生成挥发性有机物———氯化苦（硝基三氯甲烷）,气相-动态顶空进样技术可对水样液上气相空间的氯化苦进行吹脱捕集,通过气相色谱/质谱法测定氯化苦含量来间接测定苦味酸的浓度。结果表明：苦味酸浓度在1.00~20.0μg/L范围内呈良好的线性关系（r=0.9993）,方法检出限为0.40μg/L;1.00,2.50,10.0μg/L标准点测得结果的相对标准偏差（RSD）分别为12.5%、9.2%和10.5%（n=7）。对实际水样进行分析,加标回收率为102%~131%,RSD为3.5%~16.6%（n=3）。

Dynamic headspace sampling method coupled with gas chromatography and mass spectrometry（D-HS-GC/MS） for indirect determination of picric acid in drinking source water sample is established.Chloropicrin,the reaction product of picric acid and NaClO in head space of water sample,could be purged and trapped,and detected through GC/MS.Under the optimum conditions,test results show the detection limit is 0.40 μg/L,in the linear range（1.00-20.0 μg/L） the correlation coefficient r is 0.999 3,the RSD（n =7） are 12.5%,9.2%,10.5% when the concentrations of standard solutions are 1.00,2.50 and 10.0 μg/L respectively.Average values of recovery are 102%-131% in spike drinking source water samples,and RSD are 3.5%-16.6%（n=3）.