Analytical Sciences

Spectrophotometric Flow Injection Methods for Zinc Determination in Pharmaceutical and Biological Samples

Ivanise GAUBEUR,* Lúcia Helena S. ÁVILA-TERRA,** Jorge C. MASINI,*** and Maria Encarnación V. SUÁREZ-IHA***

*Centro de Ciéncias Naturais e Humanas, Universidade Federal do ABC, Rua Catequese, 242, 09090-400, Santo André, São Paulo, Brazil
**Departamento de Ciências Exatas, Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva, 714, 37130-000, Alfenas, Minas Gerais, Brazil
***Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo, Brazil

Zinc ions form a yellow complex with di-2-pyridyl ketone salicyloylhydrazone (DPKSH). This complex showed maximum absorption at 376 nm, and it was used to develop spectrophotometric flow injection methods for Zn(II) determination in different samples. Two types of flow systems were proposed. In the first system, a linear analytical curve was obtained in a concentration range from 0.217 to 4.60 mg L^-1 Zn(II), with a detection limit of 48.8 µg L^-1. In the second system, a minicolumn packed with an anion exchanger resin was used to concentrate Zn(II) as a chlorocomplex, and a linear analytical curve within a concentration range from 0.0824 to 2.06 mg L^-1 Zn(II) was obtained, having a detection limit of 13.9 µg L^-1. The developed methods were applied to biological and pharmaceutical samples, and a great compliance was observed by comparing the results with ones obtained by an atomic absorption technique.

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