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目的采用搅拌棒吸附萃取(SBSE)-热脱附-气相色谱-质谱联用法测定水样中54种挥发性有机物(VOCs)。方法涂有聚二甲基硅氧烷(PDMS)的搅拌棒置于20 ml水样中,以1 500 r/min萃取20 min后热脱附-气相色谱-质谱联用仪检测。研究了萃取体积、不同浓度Na Cl、不同浓度甲醇、搅拌棒转速和萃取时间对萃取效率的影响;分别对影响SBSE萃取效率的条件进行了优化,同时也对热脱附的时间、温度和冷阱温度等条件进行优化。结果 54种VOCs的浓度为0.5μg/L~100μg/L时,线性关系良好,相关系数(r)为0.994 3~0.999 9,检出限为0.03μg/L~6μg/L,相对标准偏差(RSD)为1.09%~5.02%,平均加标回收率为81.6%~99.6%(n=10)。结论本法简便、快速,准确度和灵敏度高,检出限低,稳定性好,干扰小,线性范围宽,无有机溶剂污染,可满足多种水样中54种VOCs的测定。
Objective To determine 54 volatile organic compounds (VOCs) in water samples by SBSE-thermal desorption-gas chromatography-mass spectrometry (GC-MS). Methods PDMS-coated stir bars were placed in 20 ml water samples and extracted by 1 500 r / min for 20 min, followed by thermal desorption-gas chromatography-mass spectrometry (GC-MS). The effects of extraction volume, different concentrations of NaCl, different concentrations of methanol, stirring bar speed and extraction time on the extraction efficiency were studied. The conditions influencing the extraction efficiency of SBSE were optimized, and the time, temperature and cold Well temperature and other conditions to optimize. Results When the concentration of 54 VOCs was 0.5μg / L ~ 100μg / L, the correlation coefficient (r) was 0.994 3 ~ 0.999 9 and the detection limit was 0.03μg / L ~ 6μg / L. The relative standard deviations RSD) ranged from 1.09% to 5.02%. The average recoveries were 81.6% -99.6% (n = 10). Conclusion The method is simple, rapid, accurate and sensitive, with low detection limit, good stability, small interference, wide linear range and no organic solvent pollution. It can meet the determination of 54 VOCs in a variety of water samples.