مشخصات پژوهش

Surfactants are composed of a polar head and a long non-polar tail, and may be classified to anionic, cationic, zwitterionic and non-ionic surfactants. With concentration increases, aggregates formed above the critical micelle concentration (CMC) are called micelles. Coacervates made up of vesicles and reversed micelles of alkyl carboxylic acids. Coacervates are also the extraction medium, called coacervative extraction (CAE). The coacervative phase formation is affected from various factors like temperature and pH [1]. In this study coacervative extraction of Co (II) as its complex with 1-(2-pyridylazo)-2-naphthol (PAN) using capric acid as surfactant and THF as solvent was optimized. After extraction of colored complexes in coacervate rich phase, colorimetric determination of the analyte was performed using digital RGB factors recorded by smartphone as analytical devise [2]. Under the optimum conditions, linear dynamic range of calibration curve was 25-250 µg L-1 and a regression coefficient (R2) of 0.9923. The limit of detection (LOD) and quantitation (LOQ) were 7.18 and 25 µg L-1, respectively. The proposed method was successfully applied for the determination of trace amounts of Co (II) in mineral water, well water and river water with recoveries of 105, 109 and 98%, respectively. The repeatability of the proposed method, expressed as the relative standard deviation (%RSD), was 4.45% for intra-day (n=5, 100 µg L-1) and 5.34% for inter-day determinations (n=3).