电子制冷预浓缩仪-气相色谱-质谱法测空气中含硫化合物

建立电子制冷预浓缩仪-气相色谱-质谱法测定空气中10种含硫化合物的方法。经考察不同采样容器、优化预处理条件、研究样品保存等获得了最佳实验条件,并通过实际样品的测定,考察了方法的适用性。结果表明:硫化氢、甲硫醇和乙硫醇3种高活性含硫化合物校准曲线线性回归系数在0.990以上,另外7种含硫化合物在0.995以上;高、中、低空白加标样品相对标准偏差均为9.5%以内,乙硫醇由于具有高活性和吸附性,低浓度空白加标回收率为63%,其余组分回收率范围为83%~110%;当进样体积为400 mL时,各目标化合物的方法检出限为0.2×10^-3~1.1×10^-3 mg/m³。分析污水处理厂无组织排放监控点的空气结果显示,该方法具有较低的检出限及较强的抗干扰能力,能较好地满足目前监测工作的要求。

Determination of Sulfur Compounds in the Air by Gas Chromatography Mass Spectrometry with Electronically Controlled Cryo-focusing Unit

This study established a method to detect 10 sulfur compounds in the air by gas chromatography mass spectrometry (GC-MS) with electronically controlled cryo-focusing unit.The best experimental conditions were obtained by selecting of different sampling containers,optimizing the pretreatment conditions and researching sample preservation experiment,and the adaptability of the method was investigated by detecting of actual samples.The study showed that the linear regression coefficients of the calibration curves of 3 highly active sulfur compounds,such as hydrogen sulfide,methyl mercaptan and ethyl mercaptan,were above 0.990,and the left 7 sulfur compounds were above 0.995.The relative standard deviations of different concentration in high purity nitrogen were all lower than 9.5%,and the recovery were in the range of 83%-110% for 9 sulfur compounds,but the recovery for ethanethiol in the low concentration was 63% because of high activity and adsorptivity.Otherwise,when inject volume was 400 mL,the limit detection of 10 sulfur compounds was 0.2×10^-3-1.1×10^-3mg/m³.Through the detection of the actual samples in the sewage treatment plant,it was proved that the method has low detection limit and stronger anti-interference ability of complex matrix,which can very suitable for determination of the sulfur compounds in the air.