Extraction and Preconcentration of Lead using Cloud Point Methodology: Application to its Determination in Real Samples by Flame Atomic Absorption Spectrometry

Jamshid L. Manzoori*, Hossein Abdolmohammad-Zadeh

Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran
Fax: +98 411 3340191.
E-mail: manzoori@tabrizu.ac.ir (J. L. Manzoori)

Abstract
1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was used as a chelating agent in cloud point extraction (CPE) for the first time and applied for the preconcentration of trace levels of lead as a prior step to its determination by flame atomic absorption spectrometry using octylphenoxypolyethoxyethanol (Triton X-114) as a nonionic surfactant. The effect of the experimental conditions such as pH of the solution, concentration of the chelating agent and surfactant, equilibration temperature and incubation time on cloud point extraction, were evaluated and optimized. In the optimum conditions, an enhancement factor of 110 was obtained for only 10 mL of water sample in the presence of 0.05% (v/v) Triton X-114. The limit of detection (LOD) obtained in the optimal conditions was 1.49 µg L^–1. The calibration graph using the preconcentration system was linear at levels 5–200 µg L^–1 with a correlation coefficient of 0.9995. The proposed method was applied to the trace determination of lead in biological and water samples.

Keywords: Lead; Cloud point extraction; FAAS; Triton X-114; PMBP