Enhancing Effect Mechanism Of Chemical Vapor Generation-atomic Fluorescence And Speciation Analysis Of Trace Arsenic In Flour

In this paper, the reaction course of chemical vapor generation and the mechanism of Enhancing effect on atomic fluorescence for arsenic,selenium, cadmium and nickel were studied.And a novel method was developed for speciation analysis of As3+ and total inorganic arsenic in flour by slurry-sampling hydride generation-atomic fluorescence spectrometry.This paper includes three chapters.Chapter one:The research advancement of hydride generation atomic fluorescence spectrometry and the application of slurry-sampling technique were reviewed with 50 referencesChapter two:The acidity of reaction medium was an important factor for the vapor generation efficiency.The effect of medium acidity on chemical vapor generation reaction was studied based on experiment and theoretically analysis.The result showed that the higher efficiency of vapor generation was observed when hydrochloric acid was used as a reaction medium with higher acidity for arsenic and selenium, and with lower acidity for cadmium and nickel.The optimal acidity range for arsenic and selenium was very broader than that for cadmium and nickel.The reaction course of vapor generation was discussed based on the transition interspace state theory. The increasing effect of complexing agents, metal ion and surfactants was investigated and compared.The mechanism of the increasing effect of 8-hydroxquinoline, phenathroline, cobalt ion, cation surfactant CTAB(Cetyltrimethyl Ammonium Bromide)and non-ionic surfactant Triton X-100 on atomic fluorescence was developed, respectively.Chapter three:A fast,sensitive method was developed for determination of As3+ and total inorganic arsenic in flour by slurry-sampling hydride generation-atomic fluorescence spectrometry. The factors that influence the suspension solution'stability and Uniformity were studied.As5+ is reduced by thiourea-ascorbate in medium of 10% HCl to determine the total inorganic arsenic.As3+ is determined in the Buffer Solution of Clark-lubs that pH=3;The content of As5+ is calculated by subtraction method.