MnO_2纳米溶胶-甲醛化学发光体系及其分析应用研究

Chemiluminescence of Nano-Colloidal MnO_2 with Formaldehyde and Its Analytical Application

Na2S2O3在中性水溶液中还原KMnO4可制备得到暗棕色的可溶性MnO2溶胶.所制备的MnO2溶胶透明、稳定,最大吸收波长位于357 nm处,平均粒径约40 nm.研究发现,所制备的MnO2纳米溶胶在酸性介质中与甲醛反应可产生弱的化学发光.考察了近30种药物分子在MnO2纳米溶胶-甲醛体系中的化学发光行为.结果表明,吩噻嗪类药物、氨基硫醇类药物等对该体系的化学发光信号具有显著的增强作用.据此,建立了利用这一化学发光体系测定五种吩噻嗪类药物和四种氨基硫醇类药物新的流动注射化学发光分析方法.所建立的方法被成功地用于片剂中奋乃静含量和猪饲料中盐酸氯丙嗪含量的测定.通过对化学发光光谱、荧光光谱、紫外可见吸收光谱等实验的研究,提出了可能的化学发光反应机理.所有反应的化学发光光谱的最大发射波长均位于630～640 nm间,与分析物的种类无关.当向反应体系中加入单线态氧清除剂叠氮化钠和三亚乙基二胺时,反应的化学发光强度被不同程度的抑制,这表明单线态氧可能是该化学发光反应的发光体.

Water-soluble forms of colloidal MnO2 were prepared by the chemical reduction of KMnO4 with Na2S203 under neutral aqueous condition. The as-prepared colloidal MnO2 solution is dark-brown, trans- parent, stable, and possesses the maximum absorption peak at 375 nm and an average diameter of 40 nm. The as-prepared nano-colloidal MnO2 was found to react with formaldehyde to generate weak chemiluminescence （CL） under acidic condition. The effects of more than 30 pharmaceuticals on the nancolloidal MnO2-formaldehyde CL system were tested. Pharmaceuticals including phenothiazines and aminoethanethiols were observed to enhance the CL signal significantly. The experimental conditions were well optimized and the analytical figures for five phenothiazines and four aminoethanethiols were presented. The method was validated by the analysis of perphenazine in tablets and chlorpromazine hydrochloride in swine feed. The CL reaction mechanism was discussed by the study of CL spectra, fluorescence spectra, UV-vis absorption spectra, and other experiments. All of CL reactions had the same maximum emission wavelength about 640 nm, which suggested that the CL emitter was independent of analytes. The CL signal was inhibited obviously by single-state oxygen scavengers, sodium azide and 1,4-diazabicyclo[2,2,2]octane, indicating that single-state oxygen dimer was the potential CL emitter for the present CL reaction.