顶空-固相微萃取-气相色谱/三重四极杆质谱法同时测定水体中51种异味物质

Simultaneous Determination of 51 Odorous Substances in Water by Headspace-Solid Phase Microextraction-Gas Chromatography/Triple Quadrupole Mass Spectrometry

  • 摘要: 本研究建立了顶空-固相微萃取-气相色谱/三重四极杆质谱法同时测定水体中10类共51种异味物质。在优化的实验条件下,探索萃取头、萃取温度、萃取时间、含盐量、解吸时间等对检测结果的影响。结果表明,选取聚二甲基硅氧烷/二乙烯基苯萃取头,向10 mL样品中加入3.0 g NaCl,55 ℃下萃取20 min后于250 ℃解吸0.5 min,以10∶1分流比进样,51种异味物质的检出限为0.4~183 ng/L,线性相关系数均大于0.995,其中土溴素、2-甲基异茨醇、苯甲醚、二甲基二硫醚、二甲基三硫醚等物质的检出限分别为0.4、0.9、1.9、3.5、1.7 ng/L,能够满足我国标准GB 5749—2022规定的限值要求;低、中、高3个水平的加标回收率分别为76.2%~118%、78.9%~119%、82.0%~119%,相对标准偏差分别为2.9%~19.4%、1.8%~13.4%、0.9%~13.2%。利用本方法检测29条河流地表水体,分别检出甲硫醇、二甲硫醚、乙酸仲丁酯等12种异味物质,浓度范围为2.2~1 651 ng/L,且各物质的多反应监测(MRM)通道没有明显干扰。该方法具有前处理简单、重现性好、准确度高等特点,适用于同时快速筛查水体中多种异味物质。

     

    Abstract: A method of headspace-solid-phase microextraction-gas chromatography/triple quadrupole mass spectrometry was established for simultaneous determination of 10 types of 51 odorous substances in water. The effects of extraction head, extraction temperature, extraction time, salt content, desorption time and split ratio on detection results were investigated with optimized gas chromatography-mass spectrometry parameters using the multiple reaction monitoring (MRM) mode for triple quadrupole mass spectrometry. The results showed that the optimized conditions were polydimethylsiloxane/divinylbenzene as extraction head, 55 ℃ as extraction temperature, 20 min as extraction time, 300 g/L NaCl as salt content, desorption time of 0.5 min and the split ratio of 10∶1. The detection limits of 51 odorous substances ranged from 0.4 to 183 ng/L, and the linear correlation coefficients were greater than 0.995. The detection limits of indicator substances, such as geosmin, 2-methylisothiol, anisole, dimethyl disulfide, and dimethyl trisulfide were 0.4, 0.9, 1.9, 3.5, 1.7 ng/L, respectively, which met the limit requirement of “Standard for Drinking Water Quality (GB 5749—2022)” of China. The spiked recoveries of the low, medium and high concentration levels were 76.2%-118%, 78.9%-119% and 82.0%-119%, and the relative standard deviations were 2.9%-19.4%, 1.8%-13.4% and 0.9%-13.2%, respectively. This method was used to detect the odorous substances in 29 surface waters, in which 12 odorous substances such as methyl mercaptan, dimethyl sulfide, and DL-sec-butyl acetate were detected with the concentration range of 2.2~1 651 ng/L. There were no apparent interferences in the MRM channels for the detected odorous substances. This method has the characteristics of simple pretreatment, good reproducibility and high accuracy, which is suitable for simultaneous and rapid screening of various types of odorous substances in water bodies.

     

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