顶空固相微萃取-气质联用法测定水中4种痕量环状缩醛类异嗅物质

Trace Level Quantification of Four Cyclic Acetals Odorous Compounds in Water by Use of Headspace SPME Followed by GC-MS

文章采用顶空固相微萃取-气质联用技术,建立了水中2,2-二甲基-1,3-二氧环戊烷(22-DMD)、2-乙基-4-甲基1,3-二氧戊环(2-EMD)、2-乙基-2-甲基-1,3-二氧戊环(2E2MD)、2-乙基-5,5-二甲基-1,3-二氧杂环乙烷(2-EDD)4种痕量环状缩醛类异嗅物质的检测方法。方法中固相微萃取前处理过程使用85μm Carboxen/PDMS萃取纤维,萃取温度为60℃,萃取时间为25 min,盐析剂氯化钠添加的质量分数为20%,色谱分离过程使用Agilent DB-5MS气相色谱柱(60 m×0.25 mm×1.00μm),内标物使用2-异丁基-3-甲氧基吡嗪。22-DMD、顺式2-EMD、反式2-EMD、2E2MD、2-EDD的方法检出限分别为1.6、0.6、0.5、1.0、0.3 ng/L,纯水、水源水、水厂出厂水和管网水平行加标样品中4种环状缩醛类物质的相对标准偏差为1.6%~8.6%,加标回收率为94%~117%,方法特性指标均满足水中痕量环状缩醛类异嗅物质的测定需要。

A detection method had been established for trace level analysis of 2,2-dimethyl-1,3-dioxolane(22-DMD),2-ethyl-4-methyl-1,3-dioxolane(2-EMD),2-ethyl-2-methyl-1,3-dioxolane(2E2MD),2-ethyl-5,5-dimethyl-1,3-dioxane(2-EDD),totally four cyclic acetals odorous compounds in water by use of headspace SPME followed by GC-MS.In SPME pretreatment period,85μm Carboxen/PDMS fiber was selected,the extraction was performed on 60℃for 25 minutes,the concentration of salting-out agent NaCl was 20%.In chromatographic process,Agilent DB-5MS column(60 m×0.25 mm×1.00μm)was applied for component separation.2-isobutyl-3-methoxypyrazine was chosen to be internal standard.The MDLS of 22-DMD,cis-2-EMD,trans-2-EMD,2E2MD,2-EDD were 1.6,0.6,0.5,1.0,0.3 ng/L respectively.The RSDs of target compounds in parallel spiked samples of pure water,raw water,finished water and distribution system water were 1.6%to 8.6%,the recovery rates were 94%to 117%.The method characteristic indices all met the determination requirements of trace level of cyclic acetals compounds in water.