吹扫捕集-气相色谱/质谱法同时测定水中的27种挥发性有机物

水中的VOCs经吹扫富集、解吸后,用HP-VOC色谱柱分离,采用全扫描和选择离子监测模式分析,内标法定量。最佳富集条件为:吹扫流速为40 m L/min,吹扫温度为40℃,吹扫时间为15 min,解吸温度为200℃,解吸时间为2 min。该法27种VOCs在一定的质量浓度范围内与其峰面积呈线性关系,相关系数r0.995,检出限为0.02~1.18μg/L。以空白样品为基体进行加标回收试验,测得回收率为79.8%~114%,相对标准偏差为0.3%~12%。

Simultaneous Determination of 27 Volatile Organic Compounds in Water by Purge and Trap Coupled with GC MS

Volatile organic compounds ( VOCs) in water sample were desorbed after purge and concentration, and then separated u-sing a HP-VOC column in gas chromatography. The MS analysis was done under both full scan mode and selected ion monitoring mode, and the quantification was done using the internal standard calibration. It was determined that the optimum conditions of the purge and concentration were purge flow of 40 mL/min, purge temperature of 40 ℃, purge time of 15 min, desorption temperature of 200 ℃, and desorption time of 2 min. Linear relationships with coefficient values r greater than 0. 995 were obtained between in-dividual peak area and mass concentration of the 27 VOCs within a defined concentration range. Method detection limits were ranged from 0. 02 to 1. 18 μg/L. Blank samples were tested for recovery rate using the standard addition method, and recovery rates were found to be in the range of 79. 8% ~114% with RSDs in the range of 0. 3% ~12%.