顶空液相微萃取-气相色谱质谱法快速测定饮料中苯和甲苯

Determination of Benzene and Toluene in Beverage by Headspace Liquid Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry

建立了顶空液相微萃取-气相色谱质谱法测定饮料中苯和甲苯的方法。在对顶空液相微萃取(head-space liquid-phase microextraction,HS-LPME)实验条件优化的基础上,确定了最佳实验条件:以1.6μL正辛醇作为有机萃取剂,在萃取温度为50℃、萃取时间为5min,搅拌速度为750r/min,液滴离萃取瓶瓶塞2.0cm的条件下,萃取4.00mLNaCl含量为4.00mol/L的样品水溶液,取0.4μL的有机萃取剂直接进样。实验结果表明,苯和甲苯的富集倍数分别为94和191,方法检出限分别为0.090μg/L和0.093μg/L,线性范围为0.5～60μg/L(r>0.999)。将该方法应用于饮料中苯和甲苯的测定,回收率为93.6%和98.0%,相对标准偏差(RSD)为3.94%和2.69%。方法简单、快速且成本低、可信度高,适用于饮料和水样中苯和甲苯的快速分析。

A novel method has been developed for the determination of benzene and toluene in beverage by headspace liquid phase microextraction （HS-LPME） coupled with gas chromatography-mass spectrometry. The variable experimental conditions for the HS-LPME extraction process were optimized. The optimized method is 1.6 μL 1-octanol as organic drop, 4.00 mL aqueous sample with NaC1 addition of 4.0 mol/L was extracted for 5 min, stirring at 750 r/min, extraction temperature set at 50℃. After extraction, 0.4 μL organic solvent was directly injected into GC-MS for detection. The enrichment factors of benzene and toluene were 94 and 191, respectively. The linear range was from 0.5 to 60 μg/L （r 〉 0.999）. Limits of detection of benzene and tolu ene were 0. 090 txg/L and 0. 093 μg/L, respectively. The method was applied to the determination of benzene and toluene in beverage, and recoveries were between 93.6% and 98.0%, the relative standard deviations were between 2.7% and 3.9%. The main advantages of the method were simple, fast, low cost and high reliable.