分光光度法测定焦糖色中4-甲基咪唑

Photometric determination of 4-methylimidazole in caramel

本文采用分光光度法对焦糖色中4-甲基咪唑进行了定量测定,克服了传统薄层法的精密度、准确度不高的弱点。实验结果表明,4-甲基咪唑经重氮化后在波长440nm处具有最大吸收,据此进行准确定量测定,重现性好。该方法灵敏度高,其线性方程为:C=0.0717A+0.0007,线性相关系数为0.999,检出限为1.4μg,RSD为3.5%。加标回收率为96%～102%。将本法用于实际样品的测定获得满意的结果。

It was observed that 4-methylimidazole was determined through a diazotisation reaction, forming a red colored azo-compound with the highly absorbance at the wave length of 440nm. Based on this phenomenon, a sensitive photometric method for the determination of 4-methylimidazole in caramel was proposed with relatively high accurancy and precision. The regression equation and correlation coefficient obtained were as follows: C=0.0717A+0.0007, r=0.999.Value of RSD(n=6) of 3.5% was obtained and recoveries were in the range 96% to 102%.This method has been applied to the anslysis of 4-methylimidazole in caramel with satisfactory results.