Factorial and Doehlert Design Used as Optimization Procedures for the Direct Determination of Lead in Whole Blood Samples by Graphite Furnace Atomic Absorption Spectrometry

Abstract

In this work, the direct determination of lead in whole blood samples by graphite furnace atomic absorption spectrometry is proposed. The samples were diluted 1:9 with HNO₃ and Triton® X-100, both 0.2% v/v. Multivariate optimization was made to evaluate the pyrolysis and atomization temperatures and the use of a chemical modifier. The method allowed lead determination with a curve ranging from 0 to 6.0 μg dL⁻¹. Recovery studies presented results from 88 to 109%. The LOD and the characteristic mass were 0.21 μg dL⁻¹ and 7.4 pg, respectively. Intra- and inter-assay studies showed respective coefficients of variation of 4.2 and 8.9%.

Keywords:

• Blood
• GF AAS
• Lead

Acknowledgments

The authors are thankful to Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for the financial support and scholarships, and the Hermes Pardini laboratory for the supply of blood samples.

Notes

*Average measured in triplicate.

*Average of triplicates.

*Recommended value for aqueous samples = 5.5 pg.

*Samples of the Interlaboratorial Program from Government of Aragon in Spain.

**MRC = Certified Reference Material (whole blood) from Bio-Rad.