通过固相微萃取富集,并采用气相色谱-质谱联用(GC-MS)测定了水中常见的两种异味化合物,即2-甲基异茨醇(2-MIB)、土味素(GSM),并对富营养化水体中的挥发性物质进行了初步分析.不同的异味物质吸附于75 μm Carboxen/PDMS纤维涂层处理后,通过DB-WAX毛细管色谱柱得以分离.采用选择离子监测模式(SIM)对两种化合物(2-MIB m/z=95,GSM m/z=112)进行外标法定量分析,从而提高检测灵敏度.线性范围2-MIB为0.5~500 ng·L-1、GSM为1.0~500 ng·L-1,检出限分别为 0.1,0.4 ng·L-1.用该法对富营养化水源水监测,2-MIB及GSM的分析结果的RSD值及加标回收率为3.35%,7.68%和105.0%,88.3%.

Hyphenated GC-MS was applied to the determination of two smelly substances,namely 2-methyl isoborneol (2-MIB) and geosmin (GSM),commonly found in eutrophic water,after their separation by solid-phase microextraction (SPME).A preliminary analysis of volatile substances in the eutrophic water was also done.Different kinds of smelly substances were adsorbed on 75 μm carboxen/PDMS fiber and separated by passing through the DB-WAX capillary chromatographic column (30 mm×0.25 mm,0.25 μm).The above mentioned smelly substances,2-MIB and GSM,were determined by GC-MS with selected ion monitoring mode,using m/z=95 for 2-MIB and m/z=112 for GSM.The sensitivity of the method was improved and linear relationship between peak area and concentration of the smelly substances were obtained in the ranges of 0.5-500 ng·L-1 (for 2-MIB) and 1.0-500 ng·L-1 (for GSM),with detection limits of 0.1 ng·L-1 and 0.4 ng·L-1 respectively.In its application to the analysis of water samples taken from the surface layer of Taihu Lake,values of RSD of the analytical results (n=8) of 3.35% and 7.68% and average recovery of 105.0% and 88.3% were obtained for 2-MIB and GSM respectively.