冷阱/吹扫捕集-GC-MS法对水中痕量烷基硫醚化合物的检测方法

Determination of Trace Amount of Alkyl Thioether in Source Water by Method of Cryotrap/Purge and Trap Extraction-GC-MS

该文介绍了冷阱/吹扫捕集-GC-MS法同时测定水体中多种痕量烷基硫醚异味化合物的分析检测方法。采用冷阱/吹扫捕集技术富集萃取了水中痕量有机硫异味类化合物,对吹扫时间、解吸时间、吹扫温度和吹扫盐度等吹扫捕集条件进行了优化,并用CP-8564型气相色谱柱分离,GC-MS/SIM进行定量测定。研究结果表明,选择吹扫温度为40℃、吹扫时间为11 min、解吸时间为2min、吹扫盐度(NaCl)为20%时,有机硫类化合物的萃取回收率可高达92.1%~99.6%。质量浓度为10 ng/L^20μg/L时,烷基硫醚化合物对应峰面积与质量浓度的线性关系良好,相关系数均在0.99以上,检出限均低于0.080μg/L,且精密度高,相对标准偏差(RSD)<4.6%。该方法针对沸点低、易挥发的化合物回收效果好,灵敏度和准确度高,简单易行,可满足实际水体中对痕量烷基硫醚异味化合物的检测要求,可显著提高水中痕量烷基硫醚化合物的分析效率。

This paper introduced a cryotrap/purge and trap extraction with the GC- MS method for the determination of various trace amounts of alkyl thioether simultaneously. The cryotrap/purge and trap extraction technology was developed to extract trace amounts of alkyl thioether in the raw water. Some factors influencing extraction efficiency of purge and trap were optimized, including purging time,desorption time,purging temperature and purging salinity. The separation was performed on a CP-8564 column. GC-MS was used to quantitatively analyze the target compounds. Experimental results indicate that purging time, desorption time, purging temperature and purging salinity（ NaCl） can be set as 11 min,2 min,40 ℃ and 20% respectively. Average recovery rates can reach to 92. 1% -99. 6%. When the mass concentration is 10 μg /L -20 μg/L,a good linear relationship between the peak area and the mass concentration of alkyl thioether is obtained with the correlation coefficients （ R2） of above 0.99. Detection limits （ MLD） of alkyl thioether are less than 0. 080μg/L. The precision of the method is high with the relative standard deviations （ RSD,n = 8 ） which is less than 4.6%,which meet the detection requirements of trace alkyl thioether. With the good recovery effect for the low boiling point and volatile compounds,the method is sensitive,accurate and simple,which meets the requirements of the detection of trace alkyl thioether in the raw water and can significantly improve the efficiency in the analysis of alkyl thioether.