全自动凯氏定氮仪测定水系沉积物、土壤、岩石全氮含量方法的优化探索

Measurement of Total Nitrogen Content in Water Sediment,Soil,and Rocks Using a Fully Automatic Kjeldahl Nitrogen Analyzer Exploration of Method Optimization

本文通过改变硫酸钾(K_(2)SO_(4))和五水硫酸铜(CuSO4·5H2O)两个联合消化催化剂比例,以及消化催化剂加入量、辛醇滴入量和浓硫酸加入量等条件,探究KII60型全自动凯氏定氮仪在测定水系沉积物与土壤中全氮含量方法的优化以及对比。该方法得出在加入硫酸钾(K_(2)SO_(4))与五水硫酸铜(CuSO4·5H2O)质量比为9:1,加入浓硫酸量为6mL,辛醇最佳滴入量2滴为最佳条件。方法检出限低至25μg/g,相对标准偏差小于2.2%,相对误差小于0.65%,测定结果与传统方法无显著性差异。该方法简便、快捷、准确度高、精密度好,环境友好型,适用于水系沉积物、土壤和岩石中全氮含量的批量测定。

This article explores the optimization and comparison of the KII60 fully automatic Kjeldahl nitrogen analyzer for measuring total nitrogen content in aqueous sediments and soil by changing the ratio of potassium sulfate(K_(2)SO_(4))and copper sulfate pentahydrate(CuSO4·5H2O)combined digestion catalysts,as well as the amount of digestion catalyst added,octanol dripping,and concentrated sulfuric acid added.This method yields the optimal conditions of adding potassium sulfate(K_(2)SO_(4))to copper sulfate pentahydrate(CuSO4·5H2O)in a mass ratio of 9:1,adding 6 mL of concentrated sulfuric acid,and adding 2 drops of octanol.The detection limit of the method is as low as 25μg/g,with a relative standard deviation of less than 2.2%and a relative error of less than 0.65%,the measurement results show no significant difference compared to traditional methods.This method is simple,fast,highly accurate,and has good precision.It is environmentally friendly and suitable for batch determination of total nitrogen content in river sediments,soil,and rocks.