控缓释氮肥释放过程中氮浓度测定方法的改进

Improvement on Method for Determination of Nitrogen Concentration during Release from Controlled-and Slow-Release Nitrogenous Fertilizers

控缓释氮肥释放过程中氮浓度的通常测定方法,主要是“凯氏氮的测定”和“碱性过硫酸钾消解紫外分光光度法”2种。但是这2种方法都有一定的缺陷,操作过程复杂,测定条件不能准确控制,测定结果可比性差,不适于氮肥释放特性的仲裁评定。通过改进“碱性过硫酸钾消解紫外分光光度法”的消解方式,可以更精确地控制消解条件。实验测定了不同样品的消解特性曲线和标准曲线。结果表明,引入恒温油浴消解的“碱性过硫酸钾消解紫外分光光度法”消解条件易于精确控制,测定结果准确,操作简便,更具有控缓释氮肥释放过程中氮浓度测定的仲裁评定。

The usual methods for the determination of nitrogen concentration during its release from controlled- and slow-release nitrogenous fertilizers are mainly the Kjeldahl determination and the ultravioler spectrophotometry with resolution by alkaline potassium persulfate, but these two methods have certain defects： their operation is complicated, the conditions of determination can not be controlled accurately, the comparability of the results of determination is poor, so they are not suitable for the arbitrary evaluation of the release characteristics of the nitrogenous fertilizers. By improvement on the resolution mode in the latter method, it is possible to control the resolution conditions more precisely. Through experiments the resolution performance characteristics and standard curves of different samples are determined. The results show that in the ultraviolet spectrophotometry with resolution by alkaline potassium persulfate the constant temperature oil bath for resolution is incorporated, then the resolution conditions are easily controlled with precision, the results of determination are accurate, the operation is simple and convenient, and it is adaptable to the arbitrary evaluation of the determination of nitrogen concentration during the release from controlled- and slow-release nitrogenous fertilizers.