Direct Photometric Determination of Lead by Manual and Flow Injection Methods with Gallocyanine

Nor Azah Yusof* and Musa Ahmad

Chemistry Department, Faculty of Science and Environmental Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor DE, Malaysia

E-mail: azah@fsas.upm.edu.my; azah@science.

Abstract

A direct photometric method was developed for the determination of sub-nanogram levels of lead. The method is based on complexation between lead and gallocyanin, which form a coloured dye (λmax 550 nm) at pH 8.0. The determination was based on the use of kinetic approach and in the lead concentration range of 1.0 × 10-3 μg/mL to 1.0 × 101 μg/mL, a smooth calibration curve was obtained. The reaction system can also be successfully adapted to flow injection analysis (FIA). The dynamic range of the proposed flow injection method was 1.0 × 10-3 μg/mL to 1.0 × 102 μg/mL and detection limit was 1.6 ng/mL at a sampling rate of 30 injections per hour. At 1:1 mole ratio of lead to the interfering ion, mercury, iron, aluminium, citrate and fluoride were found to interfere most during the determination.

Keywords

Flow injection analysis, Lead determination, Gallocyanin, Photometry.
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  • Asian J. Chem. /
  •  2009 /
  •  21(8) /
  •  pp 6190-6198