Pre-concentration of cobalt (II) ions by cloud point extraction prior to the spectrophotometric determination

A simple, fast and environment-friendly cloud-point extraction (CPE) process was described for the determination of cobalt ion. The extraction of analyte involved the formation of the hydrophobic complex between cobalt ions and ammonium pyrrolidineditiocarbamate (APDC) and then its extraction into a surfactant-rich phase. ۱ ml ethanol was added to the surfactant-rich phase prior to its analysis by visible spectroscopy. The variables affecting extraction efficiency, such as sample pH, volume of surfactant, volume of APDC solution, amount of NaCl, centrifugation conditions, bath temperature and time were optimized. Under the selected optimized conditions, the calibration graph using the proposed method for cobalt was linear in the range of ۰.۵ - ۴.۵ mg L-۱ (r = ۰.۹۹۸۱). The precision (RSD) was ۳% (C = ۱ mg L-۱, n = ۸). The enrichment factor was found to be ۱۷ and the detection limit was ۰.۰۴۵ mg L−۱. The proposed method was successfully applied to the determination of cobalt ions in real samples

کلیدواژه ها:

extraction ، cobalt ، non-ionic surfactant ، visible spectroscopy