红壤丘陵区包气带水样氨氮测定方法的改进

Improvement of measaring method for ammonia nitrogen unsaturated zone water sample in hilly red soil

对红壤丘陵农田包气带水样进行氨氮分析时,对包气带不同深度的澄清水样用氢氧化锌共沉淀处理后,用纳氏试剂分光光度法测定。该方法解决了由于水中钙、镁、铁等金属离子含量较高、酒石酸钾钠掩蔽能力不够、加入纳氏试剂后水样黄而浑问题。从浊度补偿校正、加标回收率及方法可靠性检验方面进行了对比分析,浊度补偿校正后加标回收率在98%~102%之间,经t检验p〉0.05,改进法与蒸馏法测得结果无显著性差异。

Based on the method of Nessler′s reagent photometry,the ammonia nitrogen of water sample in hilly red soil unsaturated zone was analysed through precipitation with ZnSO4 and NaOH for clarified water in different depth of Unsaturated Zone.This method solved the problems which the water samples were yellow and muddy after adding Nessler′s reagent,the masking effect of Potassium sodium tartrate was failure when the contents of Metal ions such as Ca,Mg,Fe and so on in water were higher.The comparative analysis was conducted from the compensation and correction,the return rate of standard addition and the reliability test of the method,the return rate of standard addition after the compensation and correction is 98%～102%,the results have no significant differences between the improved method and the distillation method by t test with p0.05.