Studies Of The Determination Of Heavy Metals In Biological Samples By GFAAS Using Organic Reagents As Matrix Modifiers

[Objective] The methods and the best determined condition were studied for determination of heavy metals such as Pb,Cd,Cr in biological materials by GFAAS using organic reagents as matrix modifier to develop new analytical methods which are more convenient,accurate and sensitive and provide better methods and more references for biological monitoring.[Methods] According to the concrete requests of the Chinese ministry of Health's standard《Biological materials.Methods of monitoring.Guide of development》,the heavy metals such as Pb,Cd, Cr in biological materials were determined with GFAAS using organic reagents as matrix modifier, which included sample collection and preservation, establishment for standard curves,determination of samples, selection of the best organic reagents and the best instrument work condition, examinations of detection limits,precision,accuracy, interference and sample stability.[Results]When tartaric acid and NH4H2PO3 were used to determine Lead in urine as the matrix modifier, the atomise temperature was decreased from 1500℃to 1300℃,and the background was reduced too; then added NH4H2PO3,the signal of lead absorption was decreased enormously. The detection limit was 0.03μg/L,the rates of recovery were 99.1%-102.6%,the RSD was less than 5.7%.When the cadmium in blood was determined with GFAAS using Triton X-100 as matrix modifier, the results showed that the atomization temperature was decreased from 1900℃to 1700℃,and the background was reduced too; The detection limit was 0.01μg/L,the rates of recovery were 96.0%-101.5%,the RSD was less than 6.0%.And when the determination of chromium in urine were determined with GFAAS using organic reagent as matrix modifier,after(NH4)4EDTA was applied as matrix modifier,the background were reduced obviously, the signal of chromium absorption was decreased enormously, the figure of absorption peak were improved, and the atomise temperature was decreased by a big margin.The detection limit was 0.20μg/L,the rates of recovery were 98.7%-103.0%,the RSD was less than 6.5%.[Conclusions] lead in urine,cadmium in blood and chromium in urine are determined by the methods using tartaric acid and NH4H2PO3,Triton X-100,(NH4)4EDTA respectively, which will be convenient, sensitive, low detection limits,stable,reduce the background effectively, and be low-cost environment friendly and suitable for popularization.