气相色谱-正化学源质谱法同时测定焦糖色素中2-甲基咪唑和4-甲基咪唑

Determination of 2-methylimidazole and 4-methylimidazole in caramel pigment using GC-PCI MS/MS

建立了采用气相色谱-正化学源质谱法同时检测焦糖色素中2-甲基咪唑和4-甲基咪唑的方法。样品经碱化处理后,用硅藻土净化,乙酸乙酯洗脱,采用气相色谱-正化学源质谱法测定。结果表明,在0.5~8.0μg/mL线性良好,2-甲基咪唑R^(2)=0.9997,4-甲基咪唑R^(2)=0.9994;2种物质的方法检出限均为20 mg/kg;在20、80、320 mg/kg的3个水平下,2-甲基咪唑的回收率为102.1%~107.9%,相对标准偏差(n=3)为1.33%~5.79%。该方法简单、快速、高效,可用于焦糖色素中2-甲基咪唑和4-甲基咪唑的同时测定。

Gas chromatography-positive chemical ionization-tandem triple quadruple mass spectrometry(GC-PCI MS/MS)for deter-mination of 2-methylimidazole and 4-methylimidazole residue in caramel pigment was established.The samples were first alkalized and pu-rified by kieselguhr.And then they were eluted with ethyl acetate.The detection was carried out by GC-PCI MS/MS.A good linear rela-tionship was obtained in the concentrations of 0.5-8.0μg/mL,while the correlation coefficient of 2-methylimidazole was 0.9997 and 4-methylimidazole was 0.9994 respectively.The detection limit of this method was 20 mg/kg.The recoveries of three spiked levels(20,80 and 320 mg/kg)were in the range of 102.1%-107.9%with RSDs(n=3)which between 1.33%-5.79%.This method devel-oped here was simple,rapid,sensitive and accurate to meet the needs of the analysis.And it could be used for the detection of 2-methy-limidazole and 4-methylimidazole in caramel pigment.