Optimization of emulsification-based liquid phase microextraction of chromium in seawater of Chabahar Bay for its speciation by high-performance liquid chromatography

Abstract

After complexation of Cr(III) and Cr(VI) species with diethyldithiocarbamate (0.2 mmol/L), effective parameters of emulsification-based dispersive liquid microextraction procedure was optimized for its preconcentration in artificial seawater. Triton X-305 as the emulsifying disperser and mixture of the chloroform and carbon tetrachloride as the extraction solvents show a better behavior at sample pH of 6.5. The method was applied for extraction and UV detection (λ = 254 nm) of chromium species of the Chabahar Bay seawater prior to high-performance liquid chromatography (conditions: C18, methanol: acetic acid solution 2% v (85:15), flow rate of 0.8 mL min-1). Characteristics of the method such as enrichment factor (210 and 228), linear range (10-300 μg L-1), limit of detection (0.017 and 0.597 μg L-1) and repeatability, (N = 5, concentration of 100 μg L-1 %relative standard deviation = 2.6% and 0.45%) were evaluated for Cr(III) and Cr(VI), respectively.