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为测定含大量干扰离子的水样中镍的浓度,提出一种改进的分光光度法。即以多种物质的吸光曲线回归方程,将实时测得的水样吸光度分解成多种物质的吸光度,利用多元一次方程进行求解并计算出浓度的方法。新方法在不进行修正时,对含Cr6+干扰的水样Ni2+测定的结果,误差较小。多组分的水样测量吸光度误差较大,通过引入修正系数修正后误差大幅下降。方法中Ni2+、Fe3+的吸光度与显色时间基本无关;而对于Mn2+、Cu2+和Cr6+,显色时间应控制在0.5～2.5 min内或10 min外,以保证测得吸光度值的稳定与准确。对组成不同的含Mn2+和Fe3+水样测得的Ni2+浓度分析,变异系数(CV)4.74%,检出限为0.275 mg/L,精确度和精密度较好。同时,这种规避方法还具有其他作用,可以在分析组分的同时粗略算出含量。
To determine the concentration of nickel in water samples containing a large number of interfering ions, an improved spectrophotometric method is proposed. That is to say, the regression equation of the light absorption curve of a plurality of substances is used to decompose the absorbance of the water sample measured in real time into the absorbances of a plurality of substances, and the method for solving and calculating the concentration by using a multiple linear equation. The new method without correction, the interference of water samples containing Cr6 + Ni2 + measurement results, the error is small. Multi-component water sample measurement absorbance error larger, through the introduction of correction factor correction error dropped significantly. In the method, the absorbance of Ni2 + and Fe3 + has no relation with the color developing time. For Mn2 +, Cu2 + and Cr6 +, the color developing time should be controlled within 0.5-2.5 min or 10 min to ensure the stability and accuracy of the measured absorbance. The Ni2 + concentration of different compositions containing Mn2 + and Fe3 + was 4.74% and the detection limit was 0.275 mg / L, which showed good accuracy and precision. At the same time, this method of circumvention also has other functions that allow you to roughly calculate the content while analyzing the components.