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目的建立固相微萃取(SPME)结合气相色谱-质谱法检测饮用水中5种挥发性痕量异味化合物的分析方法。方法采用CAR/DVB/PDMS纤维涂层萃取头插入装有5种标准化合物的40 m L顶空瓶中,加入6 g Na Cl,80℃下平衡20 min,吸附40 min,经过气相色谱-质谱检测,对饮用水中常见的5种致异味化合物(2-甲基异莰醇(MIB)、2,4,6-三氯茴香醚(2,4,6-TCA),土臭素(GSM),2-甲氧基-3-异丙基吡嗪(IPMP),2-甲氧基-3-异丁基吡嗪(IBMP))进行检测。分别优化固相微萃取的萃取头、加盐量、萃取温度以及萃取时间等因素。结果最优提取条件:65μm PDMS/CAR/DVB纤维头,30%(m/v)加盐量,萃取温度60℃,萃取时间40 min。5种异味化合物在1~100 ng/L范围内线性关系良好,R2>0.971,检出限分别为1.0、1.0、0.8、1.0、1.0 ng/L,精密度小于10%。结论本方法检测限低,灵敏度高,是检测饮用水样异味的良好方法。
OBJECTIVE To establish a method for the determination of 5 volatile trace malodorous compounds in drinking water by solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Methods CAR / DVB / PDMS fiber-coated heads were inserted into 40 m headspace vials containing 5 standard compounds, 6 g NaCl was added and equilibrated for 20 min at 80 ° C for 40 min. After gas chromatography-mass spectrometry (MIB), 2,4,6-trichloroanisole (2,4,6-TCA), geosmin (GSM) , 2-methoxy-3-isopropylpyrazine (IPMP), 2-methoxy-3-isobutylpyrazine (IBMP)). Optimize the extraction head, salt content, extraction temperature and extraction time of solid-phase microextraction respectively. Results The optimum extraction conditions were: 65μm PDMS / CAR / DVB fiber head, 30% (m / v) salt addition, extraction temperature 60 ℃ and extraction time 40 min. The linear range of the 5 kinds of off-flavor compounds in the range of 1 to 100 ng / L was R2> 0.971. The detection limits were 1.0, 1.0, 0.8, 1.0 and 1.0 ng / L, respectively. The precision was less than 10%. Conclusion This method has low detection limit and high sensitivity, which is a good method to detect odor of drinking water samples.