【摘要】 以尼古丁－硅钨酸作活性物质，邻苯二甲酸二（２—乙基己）酯作增塑剂，Ａｇ／ＡｇＣｌ电极为内参比电极，构成ＰＶＣ 膜尼古丁选择性电极。在２０～５５ ℃范围内，电极对１．０ ｍ ｏｌ／Ｌ尼古丁溶液的响应电位随温度增加呈线性上升趋势，温度效应系数为１．０５ ｍ Ｖ／℃。当ｐＨ 为５～７ 时，电极对８．０×１０－ ５～１．０×１０－ １ ｍ ｏｌ／Ｌ 的尼古丁标准溶液具有良好的能斯特响应，工作直线斜率为５４ ｍ Ｖ／ｐＣ。通过调节试液２５ ℃时的ｐＨ 值在２．５～８．５ 范围内变化，测量１．０×１０－ ３ ｍ ｏｌ／Ｌ、１．０×１０－ ２ ｍ ｏｌ／Ｌ、１．０×１０－ １ｍ ｏｌ／Ｌ 的尼古丁标准溶液的电位，绘制ｐＨ－ｍ Ｖ 曲线并计算求得尼古丁在水溶液中的平均电离常数值。更多还原

【Abstract】 Using nicotine silicotungstate as active material, a PVC membrane nicotine ion selective electrode was prepared. The electrode shows near Nernstian response over the concentration range of 8.0×10 -5 ～1.0×10 -1 mol/L nicotine in solutions of pH 5～7 at 25℃. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode . The influence of pH on the electrode response to different concentrations of nicotine was shown in pH mV profile. The profile was used to calculate the dissociation constants of nicotine in aqueous solutions. The average values for the pKa 1 and pKa 2 of nicotine solution measured by this method were found and compared with the literature values of 3.04 and 7.84.更多还原