固相微萃取-气相色谱-质谱联用测定水中痕量2-甲基异冰片和土臭素

摘要

A method for the determination of 2-methylisoborneol (MIB) and geosmin (GSM) in water was developed by solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry(GC-MS). The best extraction conditions were as follows: water bath heating (The level of water surface in bath was set at the same level of sample) , extraction temperature of 65 ℃ and extraction time of 30 min. The method was highly sensitive, better precisive and accuracy based on GC-MS results. The correlative coefficients for MIB and GSM were both over 0. 999; detection limits and RSD were 0. 2 ng/L, 0. 3 ng/L and 5. 8%, 3. 2% respectively! Recoveries of spiked respectively were 102. 0% and 101. 7%. The method can be used to detect MIB and GSM in water.%1 引 言2-甲基异冰片(2-Methylisobomeol,M1B)和土臭素(Geosmin,GSM)主要由放线菌、真菌和蓝绿藻代谢产生,这两种物质是目前造成饮用水具有霉昧和土味的主要原因,尽管其在样品中的含量极低,但人的嗅觉对其极为敏感,微量的这些物质便能感觉,有研究表明,人类对2-甲基异冰片和土臭素的嗅阈值分别为10和30 ng/L[1].目前,吹扫捕集(PT)和固相微萃取(SPME)技术结合气相色谱质谱法(GC-MS)是测定这两种异味物质较普遍的方法[2～4],但PT技术相比SPME技术需昂贵的仪器设备,操作也相对复杂.SPME技术多采用磁力加热方式萃取挥发性化合物[5～7],但这种加热方式需配备专门的仪器没备,升温相对较慢,而水浴加热方式鲜见报道.本研究采用水浴加热,建立了水中2-甲基异冰片和土臭素的SPME-GC-MS测定方法,为水中异味物质分析提供了参考.