分光光度法测定硅钙钾肥中水溶性硫酸根离子

Determination of Water-soluble Sulfate in Silicon-calcium-potassium Fertilizer by Spectrophotometry

以不溶性含钾岩石和磷石膏为原料制备的硅钙钾肥中含有水溶性硫酸根离子,其含量是影响硅钙钾肥产品质量的一个重要指标。本文采用铬酸钡分光光度法测定硅钙钾肥中的水溶性的硫酸根含量。于420nm波长处,硫酸根浓度在20～160μg.mL-1范围内与铬酸根吸光度呈线性关系,线性回归方程y=5.6815x-0.0242,r=0.9998。相对标准偏差优于10%,加标回收率在97%～103%之间。该方法操作简单,可行性强,可满足测定要求。

Applied the insoluble potassium rocks and phosphorous gesso as raw material,the silicon-calcium-potassium fertilizer was prepared which contained water-soluble sulfate.Its content was one of important index to affect the product quality.The method of barium chromic acid spectrophotometry was used to determine the content of water-soluble sulfate.When visible absorbance was detected at a wavelength of 420nm and concentration of water-soluble sulfate at 20 ～ 160μg/mL.Sulfate had a linear relationship with absorption of CrO42-.The linear equation was y=5.6815x-0.0242 and the correlation coefficient was 0.9998.Relative standard deviation was better than 10%,and the standard addition recovery was 97% ～ 103%.