一阶紫外导数光谱PLS法直接同时测定硝酸根和亚硝酸根

Simultaneous Determination of Nitrates and Nitrites by the Derivative Spectrophotometric Partial Least Square Method

用偏最小二乘（ＰＬＳ）法解析了ＮＯ_３~－和ＮＯ_２~－混合体系的一阶紫外导数光谱，提出了直接同时测定环境水样中ＮＯ_３~－－Ｎ和ＮＯ_２~－－Ｎ的计算分析法。该法对ＮＯ_３~－和ＮＯ_２~－来说，最低检测浓度分别为９×１０^（－８）和２×１０^（－７）ｍｏｌ·Ｌ^（－１），精密度（ＲＳＤ）分别为２．０５％和２．１２％。用于测定合成水样，平均相对误差在４％以内；用于测定环境水样，结果与标准法相吻合。

A first-derivative spectrophotometric partial least squares(PLS) method for the direct simultaneous determination of nitrates and nitrites in environmental water samples has been proposed.The detection limit is 9×10-8and 2×10-7mol/L,and the relative standard deviation is 2.05% and 2.12% for nitrates and nitrites,respectively.The method has been applied to the determination of nitrates and nitrites in real environmental water samples and artificial blends.The results agree well with those by the standard method,and the average relative error is within 4%.