基于苏丹红Ⅰ分子中的-C=C-和-N=N-基团的电活性,在悬汞电极上还原产生还原波,其还原峰高与苏丹红的浓度呈线性关系。据此提出用线性扫描伏安法测定辣椒制品中苏丹红Ⅰ的含量。试验中用悬汞电极为工作电极,饱和甘汞电极为参比电极,铂微电极为对电极,饱和硼砂缓冲溶液(pH 9.2)为支持电解质,并以丙酮作为样品的溶剂,记录在-1 050 mV处还原峰电流ip。测得苏丹红Ⅰ的质量浓度在0.1~1.4 mg·L-1范围内与其峰高呈线性关系,检出限(3s/k)为9.8 μg·L-1。用标准加入法进行回收试验,测得回收率在88.0%~98.4%之间,测定值的相对标准偏差(n=5)在0.72%~5.4%之间。

In a buffer medium of saturated borax solution (pH 9.2) acting as supponting electrolyte and using acetone as solvent for samples of chilli products, a reductive wave giving by the electro active -C=C- and -N=N- groups in the molecule of Sudan Ⅰ was observed at the hanging mercury drop electrode which is the working electrode of the 3-electrode system, with SCE as reference electrode and micro-Pt electrode as counter electrode, at the potential of -1 050 mV. Linear relationship between values of reductive peak current ip and mass concentration of Sudan Ⅰ was obtained in the range of 0.1-1.4 mg·L-1, and detection limit (3s/k) was found as 9.8 μg·L-1. Based on these facts, a linear scanning voltammetric determination of Sudan Ⅰ in chill products was proposed. Using samples of chilli sauce as matrixes recovery was tested by standard addition method, giving results of recovery in the range of 88.0%-98.4%. Values of RSD′s (n=5) calculated from the determined results were in the range of 0.72%-5.4%.