维生素B1选择性电极的研究

本文研制以四间甲苯硼酸硫胺为活性物质的维生素B₁液膜电极。在pH2～4水溶液中的线性响应范围为10^-1～10^-6M。用柠檬酸复合底液可使维生素B₁的稳定范围扩展至pH8,电极灵敏度提高一倍(线性响应区斜率54mV/△pC)。由电极的线性响应斜率与pH的关系测出质子化硫胺在柠檬酸复合底液(I=0.5)中的pK_a1)=5.04。电极响应快,稳定性好,适用于维生素B₁药物的快速分析。

STUDIES ON VITAMIN B1SELECTIVE ELECTRODE

A new vitamin B₁-selective liquid membrane electrode with thiamine-tetra(mmethylphenyl) borate ion-pair complex as active material is proposed. In aqueous solutions at pH 2～4, the electrode showed Nernst response over the Vitamin B₁ concentration range 1×10^-1M～1×10^-6 M. In the citrate buffered media vitamin B₁ was found to be stable enough even at pH 8, and the electrode showed a two-fold sensitivity in determination with cationic slope of 54 mV/concentration decade, fast response, and good reproducibility. Methods for rapid determination of vitamin B₁ in various pharmaceutical preparations are described. Ka₁ value for protonated thiamine in citrate buffer (I=0.5) was determined from the Slope-pH relation (pK_a1=5.04).