土壤交换性铝的三种测定方法比较

Comparison of Three Methods for Determination of Soil Exchangeable Aluminium

为了准确高效地检测土壤交换性铝含量,探寻适宜的检测方法。比较分析了氯化钾交换-中和滴定法、铝试剂法和羊毛铬花青R比色法所测交换性铝的差异性、精密度、准确性和适用性。结果表明,3种方法所测交换性铝无显著性差异。但羊毛铬花青R比色法的精密度优于氯化钾交换-中和滴定法和铝试剂法,羊毛铬花青R比色法平均回收率达99.28%,准确性高于另2种方法。羊毛铬花青R比色法的线性范围在0~0.32 mg/L,对应吸光值范围在0~0.778;铝试剂法的线性范围在0~0.8 mg/L,对应吸光值范围在0.006~0.157;与铝试剂法相比,羊毛铬花青R比色法的线性范围小于铝试剂法,但其吸光值范围大于铝试剂法。羊毛铬花青R比色法显色剂与显色物质吸收峰间隔较远,测定背景干扰小,方法灵敏度较高。羊毛铬花青R比色法检测单个样品的平均用时为4.2 min,检测效率高于另2种方法,且操作简捷,适用性较高。因此,推荐羊毛铬花青R比色法为土壤交换性铝的测定方法。

Suitable detection methods to accurately and efficiently detect the soil exchange aluminum content were found.The differences,precision,accuracy and applicability of the exchange-neutralization titration of potassium chloride method,the aluminum reagent method and the chromoxane cyanine R method were analyzed.The results showed that there was no significant difference between the three methods.However,the precision of Chromoxane cyanine R method was better than that of the exchange-neutralization titration of potassium chloride method and the aluminum reagent method,and the average recovery rate of the wool-chromium-green R method was 99.28%,with a higher accuracy than the other two methods.The linear range of the chromoxane cyanine R method was 0 to 0.32 mg/L,and the linear range of the corresponding absorbent value was 0 to 0.778.The linear range of the aluminum reagent method was 0 to 0.8 mg/L,and the corresponding absorbent value range was 0.006 to 0.157.Compared with the aluminum reagent method,the linear range of chromoxane cyanine R method was smaller than that of the aluminum reagent method,but its absorbent value range was larger than that of the aluminum reagent method.The color rendering agent of the chromoxane cyanine R method was far from the absorption peak of the color rendering substance,the background interference was small,and the method sensitivity was higher.The average time of a single sample was 4.2 min,the detection efficiency was higher than that of the other two methods,and the operation was simple and the applicability was higher.Therefore,the chromoxane cyanine R method was recommended for the determination of soil exchange aluminum.