【目的】探讨用孔雀绿比色法测定 KCl 稀盐溶液浸提磷的适宜条件.【方法】利用标准溶液和不同利用方式的土样，比较不同浸提和显色条件对稀盐溶液 - 孔雀绿法灵敏度和精密度的影响.【结果和结论】浸提适宜条件如下：土水比为 1 g土∶20 mL 水，震荡时间为0.5 h，浸提剂（氯化钾）浓度为0.02 mol·L-1；显色体系中各溶质适宜的最终浓度为：H2SO4 0.48 mo1·L-1、钼酸铵0.024 mol·L-1、孔雀绿质量浓度为0.06 g·L-1.缔合物最大吸收波长为620 nm，ρ(P) 在0~0.2 mg·L-1 范围内符合比耳定律，线性回归方程为A =3.894 3C+0.001（R2 =0.999**,A 为 D620 nm, C 为磷质量浓度），ρ(P)检出限为0.002 mg·L-1.测定结果的准确度和精密度均较高，因此本法适宜于氯化钾稀盐溶液浸提液中磷的测定.
【Objective】The method of available phosphorus characterized by phosphorus extracted in KCl dilute-salt solution was studied. 【Method】 By using standard solution and soil samples from different land use patterns, influences of different conditions during extracting and color-developing stages on the precision and accurancy of dilute-salt solution-malachite green method were studied. 【Result and conclusion】 The optimum conditions for extraction were as follows:1 g soil∶20 mL water for soil-water ratio, 0.5 h for oscillation, and 0.02 mol·L-1 for concertration of KCl extracting solution; The optimum final concentrations of reagents for the color-developing system were as follows: H2SO4 0.48 mol·L-1，(NH4) 6Mo7O24·4H2O 0.024 mol·L-1, malachite green 0.06 g·L-1. The association complex had a maximum absorption wavelength at 620 nm， and Beer’s law was obeyed in the P range of 0~0.2 mg·L-1 with the linear regression equation being A =3.894 3C+0.001（R2 =0.999**）and P detection limit being 0.002 mg·L-1， and the method had high accurancy and precision as well. Thus the method is appropriate to determine phosphorus amount in KCl extracting solution.
高雅丽,刘金山,官利兰,张新明.稀盐溶液 - 孔雀绿法测定土壤速效磷的条件选择[J].华南农业大学学报,2014,35(2):40-46复制