青岛市自来水和水源地自然水中嗅味物质的相关性研究

Correlation studies of odor substances in tap water and natural water from water sources in Qingdao

采用固相微萃取-气相色谱/质谱联用技术检测水体中痕量嗅味物质——土臭素和2-甲基异莰醇,对青岛市内四区自来水及其水源地水进行检测。参照国标GB/T 32470-2016中的检测条件,首先对比了国产和进口固相微萃取探针萃取效率,国产探针与进口探针相当,选用国产固相微萃取探针对水样进行前处理。采用2-异丁基-3-甲基吡嗪为内标物建立标准曲线,结果表明:土臭素和2-甲基异莰醇的线性范围为0~100 ng/L和2~100 ng/L,线性相关系数(r)为0.9987和0.9998,最低检出限(LOD)为0.13和0.58 ng/L,最低定量限(LOQ)为0.42和1.92 ng/L,20 ng/L和100 ng/L标准溶液重复性(RSD%,n=6)≤10.2%。对青岛市市内四区自来水及其水源地崂山水库和棘洪滩水库自然水进行嗅味物质检测,自来水中未检测到嗅味物质,崂山水库和棘洪滩水库自然水均检出土臭素,检出值分别为4.04 ng/L和1.90 ng/L,2-甲基异莰醇均有检出但均低于方法定量限。自来水和水源地自然水的加标回收率为94.9%~112.3%(加标浓度为20 ng/L和100 ng/L),加标样品重复性(RSD%,n=4)为1.3%~11.9%。

Solid-phase microextraction(SPME)coupled with gas chromatography/mass spectrometry(GC/MS)was used for the determination of trace odorants,geosmin and 2-methyli-soborneol,in tap water from four districts of Qingdao and its water sources.With reference to the testing conditions in the national standard GB/T 32470-2016,compared the extraction efficiency of domestic and imported SPME fibers,the extraction efficiency of domestic SPME fibers and imported SPME fibers were comparable,so the domestic SPME fibers were selected for the pretreatment of water samples.The standard curve was established using 2-isobutyl-3-methylpyrazine as the internal standard,and the results showed that the linear ranges of geosmin and 2-methylisoborneol were 0~100ng/L and 2~100ng/L,the linear correlation coefficients were 0.9987and 0.9998,the limits of detection(LOD)were 0.13and 0.58ng/L,the limits of quantification(LOQ)were 0.42and 1.92ng/L,and repeatability(RSD%,n=6)≤10.2%for 20ng/L and 100 ng/L standard solutions.The tap water from four districts in Qingdao and its water sources,Laoshan Reservoir and Jihongtan Reservoir natural water,were tested.Geosmin and 2-methylisobornyl were not detected in the tap water,while geosmin was detected in the natural water of Laoshan Reservoir and Jihongtan Reservoir with the values of 4.04ng/L and 1.90ng/L.And 2-methylisoborneol was detected but all were below the limit of quantification.The spiked recoveries of tap water and natural water from water sources ranged from 94.9%to 112.3%(spiked concentrations of 20ng/L and 100ng/L),and the repeatability of spiked samples(RSD%,n=4)ranged from 1.3%to 11.9%.