钾钠电极互参电位法同时测定土壤浸提液中钾和钠

Simultaneous Determination of Sodium and Potassium in Soil Extract by Ion Selective Electrode

以钾钠电极互为参比,采用一次标准加入法可以分别求出钾钠离子的浓度。电极的测定斜率为:钾53.9mV,钠52.7mV。标准混合物的测定误差分别为:钾-0.23％～+2.4％,钠-1.5％～+4.7％。实验中采用0.5mol/L BaCl_2溶液作为浸提剂及离子强度调节剂,电位法同时测定了5种不同盐化程度的(土娄)土、潮土及水稻土中钾钠的含量。回收率为:钾98.7％～102％,钠98.6％～102％.以火焰光度法作为对照,其结果与电极法完全一致。

The ion concentration of sodium and potassium can be calculated using sodium and potassium electrodes as mutual references respectively. In the method, the slopes determined by electrode were 53.9 mv for potassium and 52.7 mv for sodium. The determined errors of standard mixtures are -1.5% to +4.7% for sodium and -0.23% to +2.4% for potassium. In this experiment, five kinds of soil extracts including manured loess and wet soil in different ranges of salinization and paddy soil were determined using 0.5 mol / L BaCl2 solution as soil extractor and ionic strength adjuster. Recovery rates were 98.6% to 102% for sodium and 98.7% to 102% for potassium. At the same time, flame spectrophotometry was used as the control method. The measured results by ion selective electrode were in agreement with flame spectrophotometry.