摘要
探讨了乙酸铵交换-容量法测定土壤阳离子交换量过程中影响测定结果的关键分析条件。试验结果表明,最佳分析条件是:土壤样品粒径为20目,土壤样品与乙酸铵溶液的固液比为2 g∶50 m L,振荡频率为240 r/min、振荡时间为4 min,铵离子洗脱剂乙醇使用量为150 m L(均分3次),水蒸气蒸馏的馏出液体积为120 m L,用盐酸标准溶液容量法测定土壤阳离子交换量。结果表明,方法检出限为1.0 cmol/kg,测定下限为4.0 cmol/kg,代表性样品(p H值=5.69~8.13)测定结果的相对标准偏差为2.4%~4.6%(n=6),土壤标准样品测定结果与标准值相符,说明方法具有良好的适用性,能够满足国家土壤环境质量监测及农用地详查分析工作质量要求。
In this paper,the key analytical conditions were discussed which affected the determination results of the cationic exchange capacity in soil by ammonium acetate exchange-volumetricy method.The test results showed that the optimal analytical conditions were:the size of the soil sample was 20 meshes by grinding,the solid-liquid ratio of soil sample and ammonium acetate solution was 2g∶50 mL,the oscillation frequency was 240 r/min and the oscillation time was 4 min,the amount of ethanol used as an ammonium ion eluent was 150 mL which was divided into an average of three times,the distilled liquid volume was 120 mL which was distilled by steam.By the methods validation,the detection limit was 1.0 cmol/kg,the quantitative limit was 4.0 cmol/kg and the relative standard deviation was from 2.4%to 4.6%(n=6)in representative samples which the pH was ranged from 5.69 to 8.13,at the same time,the results of soil standard samples are consistent with the standard values.Therefore,the method had excellent applicability,and can meet the quality requirement of national soil environmental monitoring and farmland investigation.
作者
孙娟
郑玉涛
王保勤
徐荣
SUN Juan;ZHENG Yu-tao;WANG Bao-qin;XU Rong(Nanjing Environmental Monitoring Central Station,Nanjing,Jiangsu 210013,China)
出处
《环境监控与预警》
2018年第4期28-31,共4页
Environmental Monitoring and Forewarning
关键词
容量法
阳离子交换量
土壤
Volumetric method
Cationic exchange capacity
Soil
