Ferreira I M, Lima J L, Montenegro M C, Pérez Olmos R, Rios A
CEQUP/Departamento de Química Física, Faculdade de Farmácia (UP), Porto, Portugal.
Analyst. 1996 Oct;121(10):1393-6. doi: 10.1039/an9962101393.
A flow injection (FI) analytical method for the simultaneous assay of nitrite, nitrate and chloride in meat products is reported. The method is based on the potentiometric determination of chloride using a tubular ISE and on the spectrophotometric determination of nitrite. The FI system consisted in splitting the flow after potentiometric detection using a tubular detector and the subsequent confluence of the flow before reaching the spectrophotometric detector. This allowed the reduction of nitrate to nitrite in part of the sample plug on an on-line copper cadmium reductor column. Since each channel had a different residence time, two peaks were obtained for nitrite and nitrite plus nitrate. Spectrophotometric determination was made after a diazotization-coupling reaction. The results obtained were in good agreement with reference procedures and showed adequate precision (RSDs less than 6% for chloride and nitrite and 2% for nitrate). A high sampling rate was obtained (120 determinations per hour corresponding to 40 samples per hour).
报道了一种用于同时测定肉制品中亚硝酸盐、硝酸盐和氯化物的流动注射（FI）分析方法。该方法基于使用管式离子选择性电极（ISE）电位法测定氯化物以及分光光度法测定亚硝酸盐。FI系统包括在使用管式检测器进行电位检测后分流流动，并在到达分光光度检测器之前使流动随后汇合。这使得部分样品塞在在线铜镉还原柱上硝酸盐还原为亚硝酸盐。由于每个通道具有不同的停留时间，因此获得了亚硝酸盐以及亚硝酸盐加硝酸盐的两个峰。在重氮化偶合反应后进行分光光度测定。所得结果与参考方法吻合良好，并且显示出足够的精密度（氯化物和亚硝酸盐的相对标准偏差小于6%，硝酸盐的相对标准偏差为2%）。获得了较高的采样率（每小时120次测定，相当于每小时40个样品）。
