Analytical performance of ETAAS method for Cd, Co, Cr and Pb determination in blood fractions samples.

An electrothermal atomic absorption method (ETAAS) for direct determination of several toxic trace elements (Cd, Co, Cr, Pb) in human blood fractions was developed, because of increasing interest of toxic elements distribution in various blood constituents. Zeeman background correction and pyrolitically coated graphite tubes with L'vov platforms were used. Centrifugation was employed for the separation of blood fractions at different centrifugal conditions at 1200 x g and 3000 x g. The samples were acid-digested by HNO(3) in closed tubes under high temperature and pressure before injection into graphite furnace. Two common modifiers were used and were compared for their effectiveness to the determination of each analyte at the examined blood fractions. The effect of modifier, matrix, calibration technique and peak characteristic (peak area and peak height) on the total variation of the method was examined by analysis of variance. The sensitivity and recovery (Cd 98-110%, Cr 93-109%, Co 95-106% and Pb 91-107%) of the developed method are presented for the various fractions. The overall precision (R.S.D.) using peak area (Cd 6.3-13.1%, Cr 8.2-13.9%, Co 7.4-8.5% and Pb 7.0-11.8%) and peak height measurements (Cd 1.1-9.3%, Cr 6.5-13.5%, Co 6.5-17.3% and Pb 6.9-14.8%) are also presented for pellet and supernatant solution. Standard addition technique was more accurate in terms of analyte recovery.