Cloud Point Extraction and Spectrophotometry in the Determination of As(III) Using Amaranth in Water Samples of Rivers Located in Industrial and Non-Industrial Areas

Cloud-point extraction (CPE) method was employed for the extraction of trace quantities of arsenic(III) (As(III)) from various water samples using spectrophotometry. For this mixed micelle-mediated extraction, amaranth, Triton X-114, cetyl trimethylammonium bromide (CTAB) and NaCl were applied as chelating, sensitizing agent, extraction and co-extraction agents respectively. The various effective parameters on CPE, including pH, type of surfactants and electrolytes, concentration of chelating agent, surfactant, sensitizing agent (CTAB), electrolyte, temperature and duration were investigated. Additionally, analytical performance was estimated (limit of detection, recovery, sensibility and relative standard deviation (RSD) and linear range). A linear calibration curve in the range 30-1500 μg I^-1 of amaranth was acquired. Under the optimized conditions, the limit of detection (LOD) was 2.8 μg I^-1 and RSD for 300 and 600 μg I^-1 was 2.23 and 1.73 respectively (n = 10). LOD was found to be 2.8 μg I^-1. The regression equation acquired by the least square method is A = 2.05 × 10^-3 C_As + 1.21 × 10-2 for 30-1500 μg I^-1 of As(III) with a correlation coefficient of 0.997 (n = 12), where A is the absorbance and C_As is the concentration of As(III) (μg I^-1). The results indicate that the As(III) quantity in water samples of the rivers located in industrial areas is considerably higher than that in the non-industrial areas.