Form Of Indirect Determination Of Chromium. Line Preconcentration And Separation Of The Flow Injection - Flame Atomic Absorption Spectrometry Analysis

Flow injection analysis (FIA), put farward by Ruzicka and Hansen in 1975, has developedrapidly in a short time after its appearance, especially in the field of flow injechon on-linepreconcentration and separation. One of the most successful application of this technique is thecombination with atomic absorption spectrometry (AAS), which has not only enhanced thesensitivity and selectivity of AAS, but also expended the analytical objects of AAS from metalelements to various anions and organic compounds, so has introduced new vitality into theclassical analytic method of AAS. Our paper just right concentrates on the indirect determinationby flame atomic absorption spectrometry with flow injection on-line preconcentration andseparation.There are two parts in this thesis.Part one: reviwe●The new development of combination between flow injection on-line preconcentration andseparation and flame atomic absorption spectrometry.●The indirect determination flow injechon by flame atomic absorption spectrometry.●The Speciation of Chromium.Part two: research paperFirst, a direct rapid and sensitive method for the determination of speciation of chrodrium inwater samples by on-line preconcentration and separation flame atomic absorption spectrometrywas developed. Cr(Ⅵ) and Cr(Ⅲ) could be adsorbed simutaneously by one cation and one anionresin microcolumn and were eluted directly to the nebulizer by HNO₃ and NH₄NO₃+VcresPectively·The successful seParation and Preconcentratlon of Cr(皿)from Cr(w)also lay thefoundatlonforthe followinglndlrectdetermlnatlon of肌S． Then,a very sl呷ie continuous—low procedure for the determination ofascorblc acldlntablets,Injection liquid and veget劝les Is proposed．Crw)could be reduced on—line to Cr皿)by ascorbic acid In acid media．The produced Cr(皿)Is retained on a catlon一exchange resinmlcrocolumn,then elutedto the nebullzerby nitric acldandmeasuredbyAAAAS．The止sorptionofCr(皿)was ptopomonal to the ascorbic acid concentration In the sample．So the ascorbic acidcould be dete。ned by measunng the abso力ance of Cr(皿)． In order to improved the selectivity,we use Fe(皿)Instead of Cr(w)and present another。ystem to detect asco比Ic acid．In the same way Fe(m)was reduced to Fe(11)by ascorbic acid．The Fe(11)producedls adsorbedon the catlon一exchange mlcrocolumn,andthe excessive Fe(m)reacts with NH。F to form［FeF。r and passes through the nucrocolumn to be waste．Ascorbicacid couldbe detectedby me�'�＂ring the abso山ance ofFe(11),Which Is eluted from themlCrocolumnby HNO3 andmeasuredby肋S． FluJy,we have designed a simple and rapid method for the determination ofnomoxacln byon一line preconcentratlon and separation with came atomic absorption spectrometry．No占oxacln could react with Fe(皿)and form a catlon complex In acid medium．Then thecomplex Is adsorbed on a catlon resin nucrocolumn while the surplus Fe(m)ix with NH。F tobe waste In form of［FeF6F．The adsorbed complex was elu比d by HNO。and measured by AAS．Sothe nomoxacln couldbe determlnedlnthls way．...