流动注射双安培法测定桑枝中桑色素

Flow Injection Blwmperometrlc Analysis of Morin

利用桑色素在经预阳极化处理的铂电极上的催化氧化和不可逆电对的双安培检测原理,建立流动注射双安培法直接检测桑色素的电化学新方法。使用经过恒电位预阳极化处理的双铂电极,在外加电位差为0V时,通过偶合桑色素在一支电极上的氧化和氧化铂在另一支电极上的还原两个不可逆电极过程,构成流动注射双安培检测体系。结果在0.1mol/L的NH3·H2O—NH4Cl(pH=11.0)缓冲液中,测得桑色素的氧化电流与其浓度在4.0×10-6～1.0×10-3mol/L范围内呈线性关系(r= 0.9991 ,n=14)。检出限为1.0×10-6mol/L。连续35次测定2.0×10-5mol/L桑色素,电流值RSD=1.7 %。

A simple, rapid, and accurate electrochemical method for on-line determination of morin- flow in-jection biamperometry is based on the electrocatalytic oxidation of morin at preanodized platinum electrodes and the biamperometry detection principle of use irreversible electron couple system .Using two preanodized platinum electrodes with the applied potential difference of 0V, the biamperometric detection system has been established by coupling the oxidation of morin and the reduction of platinum oxide. Under the applied potential difference of 0V,in the 0.1mol/L NH 3 ·H 2 O-NH 4 Cl buffer solution (pH=11.0),the linearity between oxidizing current and morin concentration was obtained over the range 1.0×10 -6 ～1.0×10 -4 mol/L,with the detection limit 5.0×10 -7 mol/L.The relative standard derivation of 1.7 % was obtained by 56 successive determination of 1.0×10 -5 mol/L morin.