基于电导率差值法测定烟叶中钾含量的方法研究

Study on Determination Method of Potassium Content in Tobacco Leaves Based on Conductivity Difference Method

本研究建立了采用电导率差值检测烟叶中钾含量的方法。该方法利用溶液中钾离子与四苯硼钠反应后形成四苯硼钾沉淀,通过检测待测溶液反应前后溶液的电导率变化,计算出待测溶液中的钾离子含量。结果表明,利用KCl与四苯硼钠反应后,溶液电导率下降值与钾含量成正相关。在25℃条件下,钾离子浓度在0~596 mg/L范围内,标准曲线为y=1.180 2x。通过向提取液中添加一定质量的钾,计算得出钾回收率在98.66%~101.01%之间,表明该方法有较高的准确度。该方法结果与传统沉淀法检测结果基本一致,该方法检测值比火焰光度法检测的结果偏高,但重复性较好。

This study established a method to detect the potassium content of tobacco leaves by using the conductivity dif-ference method. Based on the principle that potassium ions in the solution can react with sodium tetraphenylborate to form potass-ium tetraphenylborate precipitation, the potassium ion content in the solution was calculated by detecting the change in conduc-tivity of the solution before and after the reaction. The results showed that after KCl reacted with sodium tetraphenylborate, the decrease value of solution conductivity was positively correlated with the potassium content. Under the condition of 25 ℃, the potassium ion concentration was in the range of 0-596 mg/L, the standard curve was y=1.180 2 x. By adding a certain amount of potassium to the extract, the potassium recovery rate was calculated to be 98.66%~101.01%, indicating that the method had high accuracy. The results of this method were basically the same as that of the traditional precipitation method. The detection values of this method were higher than that of the flame photometric method, but the repeatability was better.