光度法检测地表水中硝酸盐氮、亚硝酸盐氮对朗伯-比尔定律的偏离

The deviation of the Lambert- Bill law from determination of NO_3^-- N,NO_2^-- N in surface water by spectrophotometry

基于分光光度法检测地表水中硝酸盐氮、亚硝酸盐氮存在的问题,本文从实验操作的层面探讨了导致朗伯-比尔定律偏离(标准曲线的相关系数R2偏离"1")的因素:(1)通过改变溶液的浓度和光程、选择不同的波长调整合适的吸光度读数范围可降低仪器的读数误差;(2)标准使用液的体积与稀释(定容)容积的准确度决定标准溶液浓度实际值与理论值之间的偏离,其中稀释(定容)容积的影响更大,可通过容量仪器的校正(体积校正和/或称量校正)加以解决。

Based on the problems of the determination of the NO3- -N, NO2- -N in surface water by spectro-photometry , this paper discussed the causes of deviation from Lambert-Beer law （ whether the curve correla-tion coefficient, R2 was deviated from＂1＂） on the operation level. The results were listed below： （1） In or-der to reduce the instrument reading error, we may adjust the solution concentrations, changed the cuvette length and optimize the wavelength to fit the absorbance range; （2） The main infect factors were the deviation＆amp;nbsp;between actual value and theory value of the standard solution concentration. The accuracy of the working so-lution volume and dilution volume were the main factors, and the later may affect more. It can be resolved through the calibration of the capacity instrument, including volume correction and weighing correcti