蒸气顶空富集装置-自动顶空气相色谱法在海水中痕量苯系物检测中的应用

采用蒸气顶空富集-自动顶空气相色谱法,研究了海水中痕量苯系物(包括苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯和苯乙烯)的测定方法,优化了蒸气富集作为海水中苯系物预处理方法的参数。对其精馏管长度、回收冷凝液体积、吸收介质等影响富集效果的关键因素进行了评价,并优化了色谱条件,考察方法的精密度和回收率。结果表明,大体积水样经过10 cm长度冷凝管的二次冷凝富集,以水作为吸收剂,1 L水样富集浓缩至10 mL后,可使原有自动顶空气相色谱分析苯系物的灵敏度提高1~2个数量级。采用蒸气顶空富集-顶空气相色谱法测定海水中的苯系物的平均加标回收率为83%~113%,相对标准偏差为1.1%~5.4%(n=3);苯系物的海水中检出限为0.02~0.1μg/L。本文建立的蒸气顶空富集-自动顶空气相色谱法简单快速,重现性好,回收率高,适用于海水中痕量苯系物的分析测定。

Determination of Benzene and Its Analogies in Sea Water with a Vapor Dynamic Headspace Enrichment Equipment and Automatic Headspace - Gas Chromatography

BTEX（including benzene,toluene,ethylbenzene,p,m,o - xylene and styrene）in sea water determined by a vapor dynamic headspace enrichment euipment and automatic headspace - gas chromatography. The main operating parameters of this enrichment device,such as length of distillation tube,Enrichment conditions for the water preparation were optimized through a series of tests. The chromatography condition was optimized,and the method recoveries with the relative standard deviations were evaluated. The results showed that one liter of water sample could be concentrated to 10 mL throuth twice distillation and the sensitivity of traditional automatic headspace - gas chromatography could be improved 1 ~ 2 orders of magnitude. The range of average recovery was 83% ~ 113% ,the RSD was 1. 1% ~ 5. 4%（n =3）,and the detection limit was 0. 02 ~ 0. 1 μg/ L for the determination of BTEX in seawater by the vapor dynamic headspace enrichment euipment and automatic headspace - gas chromatography. This proposed method offered a number of benefits including simple,rapid,good reproducibility,high recovery and suitable for determination of BTEX in sea water.