采用乙腈为蛋白沉淀剂对血浆进行预处理,用均匀设计法安排实验,考察了血浆中硝普钠的代谢物硫氰酸盐与硝酸铁试液的反应条件。确定在456 nm测定其吸收度,测得SCN~-在1.68～13.4μg/ml的范围内与吸收度成线性关系(r=0.9999)。人体血浆中硫氰酸盐的相对平均回收率为94.0%,日内相对标准偏差在3.2%以下(n=10),日间相对标准偏差在4.0%以下(n=8)。最低检测限为0.3μg/ml。利多卡因等药物对测定无影响。 Acetonitrile was used as a protein precipitant to pretreat the plasma, and experiments were conducted with a uniform design method. The reaction conditions of thiocyanate, a metabolite of sodium nitroprusside in plasma, and a ferric nitrate test solution were examined. It was determined that the absorbance was measured at 456 nm and the linear relationship between the SCN~- and the absorbance in the range of 1.68 to 13.4 μg/ml (r=0.9999) was determined. The relative average recovery of thiocyanate in human plasma was 94.0%, the relative standard deviation was less than 3.2% (n=10), and the relative standard deviation was less than 4.0% (n=8) during the day. The limit of detection is 0.3 μg/ml. Lidocaine and other drugs have no effect on the measurement.