DETERMINATION OF TOTAL CHROMIUM IN WHOLE-BLOOD, BLOOD COMPONENTS, BONE, AND URINE BY FAST FURNACE PROGRAM ELECTROTHERMAL ATOMIZATION AAS AND USING NEITHER ANALYTE ISOFORMATION NOR BACKGROUND CORRECTION

Fast furnace program (total furnace time <45 s) electrothermal atomization atomic absorption spectrometric (ETA-AAS) determinations of total Cr in several clinical materials were carried out in conventional (DABC) and transverse (ZEBC) heated graphite atomizers. Before spectrometric determination, test portions of the samples were diluted at different ratios in appropriate solvents: (a) whole blood (WB), blood plasma (BP), blood serum (BS), and red blood cells (RBC), 1 + 4 in 0.1% (v/v) Triton X-100; (b) urine (U), 1 + 4 in 0.1% (v/v) Triton X-100 + 0.01 mol/L nitric acid; and (c) bone (B) specimens and the certified reference materials after microwave mineralization, 1 + 9 in 0.01 mol/L nitric acid. The refractoriness of Cr allowed pyrolysis at a high temperature (similar to 1650 degrees C). As a consequence, two facts arose: first, isoformation was unnecessary; and second, background correction, independent of use of continuum source (DABC design) or Zeeman effect (ZEBC design) correction, was not required. For these reasons, the fast furnace program ETA-AAS analyses were simply done by automatic injection of 10-mu L aliquots of the diluted test portions (or aqueous Cr standards) into either pyrolytic graphite-coated graphite tubes (DABC design; wall atomization performed) or pyrolytic graphite-coated graphite tubes with integrated pyrolytic graphite platforms (ZEBC design; integrated platform atomization performed), using neither analyte isoformation nor background correction; wall atomization in coated tubes was preferred. Under these experimental conditions, the limits of detection (3 sigma, mu g/L Cr) and the characteristic masses (pg of Cr) were 0.03 and 2.7 (DABC design) and 0.2 and 5.0 (ZEBC design), respectively. Accuracy was verified by analyzing human serum, freeze-dried urine, whole blood, pond sediment, tea leaves, vehicle exhaust particulates, and sargasso reference materials. Recoveries ranged from 94 to 103%. Average RSD (%) was 3.1 (DABC design) and 3.7 (ZEBC design) for both the within- and between-run precision. The proposed methods were used to establish the Cr ranges (mu g/L) of chronic renal failure patients (WB 1.8-15.7; BP 1.2-7.9; BS 0.6-3.1; RBC 2.1-20.9; B 1.7-11 mu g/g; no urine output), diabetic subjects (WB 3.5-17.8; BP 0.6-4.5; BS 1.8-13.4; RBC 3.0-7.0; no bone biopsy; U 12.0-32.6), and healthy adults (WB 4.0-5.1; BP 0.7-4.3; BS 0.5-2.0; RBC 3.0-7.0; B 0.2-2.9 mu g/g; U 2.0-9.8) of Maracaibo City. Chromium quantification was reliably and successfully accomplished.