土壤交换性铝的三种测定方法比较

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。

Comparison of Three Methods for Determination of Soil Exchangeable Aluminium

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.