Cloud Point Extraction Using NDTT Reagent for Preconcentration and Determination of Copper in Some Environmental Water Samples by Flame Atomic Absorption Spectroscopy

Pourya Biparva and Mohammad Reza Hadjmohammadi*
Department of Chemistry, University of Mazandaran, Babolsar, Iran
E-mail: p.biparva@umz.ac.ir

Abstract
A micellar-mediated phase separation using Triton X-114 was applied for preconcentration of copper, by formation of a complex with 6-(2-naphthyl)-2,3-dihydro-as-triazine-3-thione (NDTT) reagent, and its analysis by flame atomic absorption spectrometry (FAAS).The effect of experimental conditions such as pH, concentration of reagent and surfactant, equilibration temperature and time on cloud point extraction for maximum recovery were investigated. The complex of copper with NDTT was quantitatively extracted by Triton-X114 at 40 °C, then acidified methanol was added to surfactant-rich phase to decrease the viscosity for measurement of copper. The optimum conditions were pH = 8.5 using borate buffer, 0.05% (v/v) Triton X-114 and 3 × 10^–6 mol L^–1 of NDTT. Calibration graph of copper under optimum conditions was linear in the range of 0.22-100 ng mL^–1 with a correlation coefficient of 0.998 and limit of detection of 0.22 ng mL^–1. The relative standard deviation (R.S.D.) for 5 replicate measurements at 50 ng mL^-1 Cu level was 2.1% and the enrichment factor for this determination was 22.4. Finally, the proposed method was successfully applied for copper determination in some environmental water samples.

Keyword: Cloud point extraction, copper, triton X-114, NDTT, flame atomic absorption spectrometry