流动注射-共振瑞利散射法测定某些局部麻醉药物

在稀盐酸介质中, 12-钨磷酸(TP)分别与丁卡因(TC)、普鲁卡因(PC)和利多卡因(LC)等局部麻醉药反应形成离子缔合物, 导致溶液的共振瑞利散射(RRS)显著增强. 它们的最大RRS峰位于345 nm(TP-TC), 368 nm(TP-PC)和379 nm(TP-LC), 并且在一定范围内, 麻醉药的浓度与散射强度呈线性关系, 据此建立流动注射-共振瑞利散射联用技术测定丁卡因、普鲁卡因和利多卡因的新方法, 不同麻醉药的检出限在0.5~9.5 ng/mL之间. 以灵敏度最高的丁卡因为例, 试验了共存物质的影响及分析应用, 表明方法具有良好的选择性和较高的重复性; 用于尿样中TC的测定, 加标回收率为98.8%~103.2%; 对于质量浓度为2.0 μg/mL的TC进行9次平行测定的相对标准偏差为1.7%; 进样频率为60 h-1. 采用量子化学AM1法计算了3种药物的电荷分布, 并从药物结构差异上讨论了反应机理.

Determination of Some Local Anesthetics by Resonance Rayleigh Scattering Method Coupled with Flow Injection Analysis

In hydrochloric acid medium, 12-tungstophosphoric acid(TP) reacts with some local anesthetics such as tetracaine(TC), procaine(PC) and lidocaine(LC) to form ion-associate complexes, resulting in a significant enhancement of resonance Rayleigh scattering(RRS) and appearance of new RRS spectra. Their maximum scattering peaks were at 345 nm(TP-TC), 368 nm(TP-PC), 379 nm(TP-LC), and the RRS intensities are proportional to the concentrations of the three local anesthetics in a certain range. Therefore, a novel method for the determination of TC, PC and LC by RRS coupled with flow injection analysis(FIA) was deve-loped, and the detection limits(3σ) were 0.5—9.5 ng/mL for different local anesthetics. Taking the TC-TP system with the highest sensitivity as an example, the effects of coexisting substances and analytical application were studied. The results show that the method has good selectivity and reproducibility. The recovery of the present method applied to the determination of TC in urine sample was 98.8%—103.2%. And the relative standard derivation for 9 successive determinations of 2.0 μg/mL TC was 1.7% with sampling frequency of 60 h-1. In addition, the charge distribution of three anesthetics was calculated by quantum chemistry AM1 method, and the reaction mechanism was discussed from the difference of the anesthetics structure.