全自动凯氏定氮仪测定化肥中的含氮量

Determination of Nitrogen Content of Fertilizer by Automatic Kjeldahl Apparatus

建立全自动凯氏定氮仪检测化肥中氮含量的分析方法。称取总氮量在0.03-0.3 g范围的样品，经消解仪消解及全自动凯氏定氮仪碱化蒸馏，以硼酸为接收液，用0.15-0.20 mol／L的盐酸标准溶液进行自动滴定。该方法加标回收率为99.0%-101.5%，测定结果的相对标准偏差小于1.0%（n=6）。与国标GB／T 8527-2010法测定结果无显著性差异，全自动凯式定氮仪法的准确度、精密度均优于国标方法，而且所用试剂少、分析时间短，满足实验室快速检测大批量化肥中含氮量的需要。

The method for the determination of nitrogen content in fertilizer by automatic Kjeldahl apparatus was established. Sample which total nitrogen ranged from 0.03 to 0.3 g was digested in microwave, alkali-distilled in the automatic Kjeldahl apparatus. Boric acid was used as receiving solution, and 0.15-0.20 mol/L hydrochloric acid standard solution was used for automatic titration. The recoveries of the method was in the range of 99.0%-101.5%, the relative standard deviation was less than 1.0%（n=6）. Results detected by the method were compared with those deteced by GB/T 8527-2010 method. It was indicated that there was no significant difference between the two methods. The accuracy,precision of automatic Kjeldahl apparatus method were better than the standard method. The automatic Kjeldahl apparatus method costs less reagent, short time, and it can meet the rapid detection requirement of nitrogen content in fertilizer in mass work for laboratory.