单扫示波极谱法测定液体乳制品中硝酸盐

DETECTION OF NITRATE IN LIQUID MILK PRODUCTS BY OSICILLOPOLAROGRAPHIC METHOD

探讨用极谱催化法测定液体乳制品中硝酸盐含量的快速分析方法．根据在0．1mol／LNH4Cl-4×10^-4mol／LYb（Ⅲ）底液中，NO3^-在峰电位（Ep）为-1．50V（vs·SCE）处产生一个灵敏的二阶导数极谱催化波．NO^3-浓度在0．1～3．0mg／L范围内与波高（ip）呈良好的直线关系，检出限（3S／N）为0．1mg／L，回收率为92．4％～108．8％，RSD为1．7％～5．9％．建立了用单扫示波极谱催化法测定液体乳制品中硝酸盐的快速分析方法．操作简便，无需通氮除氧，用于实样分析，结果满意．

Study the rapid analytic method of nitrate content in determining liquid milk products by Osicillopolarographic method. In the solution of 0.1 mol/L NH4Cl - 4 × 10^-4 mol/L. Yb（ Ⅲ ）, nitrate produces a sensitive polarographic catalytic wave of second order derivative at peak Ep - 1.50 V（vs· SCE）, The nitrate content is proportional to peak current in the range of 0.1- 3.0mg/L. The determination limit（3S/N） is 0.1 mg/L, the recovery rate is 92.4% - 108.8% and relative standard deviation（RSD） is 1.7% - 5.9%. In the study, a rapid analytic method of nitrate content has established in determining liquid milk products by polarographic catalytic method. The method is simple to operate. It mustn＇t add to nitrogen（N2） and remove oxygen（O2）. When it is used to determine samples, the results are very satisfactory.