基于3,3',5,5'-四甲基联苯胺光热法检测维生素C

Determination of vitamin C based on the photothermal effect of 3,3',5,5'-tetramethylbenzidine

构建了一种基于3,3’,5,5’-四甲基联苯胺(TMB)的光热效应检测饮料中维生素C含量的方法。TMB在木瓜蛋白酶催化作用下可与过氧化氢反应,生成蓝色的氧化态产物(ox-TMB)。由于ox-TMB具有强烈的光热效应,吸收808 nm近红外光后可将其转换为热能,从而导致溶液温度升高;维生素C存在时可以将一部分ox-TMB还原,导致温度增量下降,且下降的温度增量与维生素C的浓度在5.0~125μmol/L范围内存在线性关系,检出限为2.3μmol/L。该方法仅用笔式数字温度计作为信号读取器,已成功用于市售饮料中维生素C的定量检测。本文所提出的策略为开发低成本的生物和临床诊断方法提供了一种新的思路。

A new method for the determination of vitamin C in beverages was developed based on the photothermal effect of 3,3',5,5'-tetramethylbenzidine(TMB).TMB can react with hydrogen peroxide in the presence of papain to form the blue oxidized product(ox-TMB),which exhibits a strong photothermal effect.The ox-TMB can adsorb 808 nm near-infrared light and transform the analysis signal into heat,leading to a rise in solution temperature.In the presence of vitamin C,a part of ox-TMB can be reduced to TMB,resulting in the decrease of temperature increment.There was a linear relationship between the concentration of vitamin C and the temperature increment in the concentration range of 5.0-125μmol/L,with a limit of detection of 2.3μmol/L.This method only uses an easily operated pen-style digital thermometer as the signal reader,and was successfully applied to the quantitative detection of vitamin C in commercial beverages.The proposed strategy may provide a new way for the development of low-cost biological and clinical diagnostic methods.