盐酸丁卡因-赤藓红反应体系的吸收光谱及分析应用

建立一种测定盐酸丁卡因的分光光度新方法。 在pH=4.0的Britton-Robinson（BR）缓冲溶液中，盐酸丁卡因（TC·HCl）与赤藓红（ET）形成1∶1的离子缔合物，导致溶液的吸收光谱变化，除在516 nm处产生明显的褪色作用外，并在558 nm处出现增色现象。 TC·HCl在0.1×10^-6~7.2×10^-6 g/mL范围内其质量浓度与褪色波长和增色波长处的吸光度变化值均呈良好的线性关系。 褪色法和增色法的摩尔吸光系数（ε）分别为3.30×10⁴和2.22×10⁴ L/(mol·cm)。 当用双波长叠加法时，ε值为5.52×10⁴ L/(mol·cm)。 研究了适宜的反应条件和分析化学性质，并结合量子化学AM1法讨论了反应机理。 方法用于人血清及尿样中盐酸丁卡因的含量测定，回收率在98.1%~103.3％之间。

Absorption Spectra of Reaction System of Tetracaine Hydrochloride with Erythrosin and Its Analytical Application

In a Britton-Robinson(BR) buffer solution of pH=4.0, erythrosine reacted with tetracaine hydrochloride(TC·HCl) to form a 1∶1 ion-association complex. As a result the absorption spectra of solution changed, and an obvious fading peak at 516 nm and a coloring revealing peak at 558 nm appeared. In the range of 0.1×10^-6 to 7.2×10^-6 g/mL, there is linearity between the concentration of TC·HCl and absorbency of the solution at the fading peak and coloring revealing peak. Based on it, a new spectrophotometry for the determination of TC·HCl was proposed. The molar absorptivity is 3.30×10⁴ L/(mol·cm) for the fading method, 2.22×10⁴ L/(mol·cm) for the revealing method and 5.52×10⁴ L/(mol·cm) for the dual-wavelength method. The optimum reaction conditions and primary chemistry characteristics were discussed. The reaction mechanism was dicussed by quantum chemistry AM1 method. The method has been applied to the determination of TC·HCl in human serum and urine samples with satisfactory results. The mean recovery is from 98.1% to 103.3%.