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@science.


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.


Flow injection analysis, Lead determination, Gallocyanin, Photometry.
   View Article PDF File Under a Creative Commons License
  • Asian J. Chem. /
  •  2009 /
  •  21(8) /
  •  pp 6190-6198