LAUSR

Abstract The authors, in the present work, described a new microvolume spectrophotometric method for extraction, preconcentration and determination of extremely low quantities of bismuth in waters and roadside soil. The strategy of method is based on the formation of an ionic pair between [BiI4]− and trioctylamine [TOA]+ in aqueous phase and extraction of this ion associate by cloud point extraction technique (CPE) using Triton X-100. The influence of different empirical parameters e.g. pH of aqueous phase, surfactant concentration, equilibrium time and temperature on performance efficiency of developed method was studied and then optimized. On the optimum conditions, the absorbance of Triton X-100 – rich phase measured at 342 nm was linear with bismuth quantity in aqueous phase in the range of 10–1250 μg L− 1 with R = 0.996, n = 7. The limit of detection (LOD), quantitation (LOQ), and preconcentration factor (CF) were calculated to be 2.86 and 9.54 μg L− 1, and 40, respectively. The evaluation of method was performed by monitoring bismuth in sea, and tap waters and roadside soil, where, the recovery percentage obtained (> 96%) proved the precision of our method. On the other hand, thermodynamic characteristics in terms of ΔH, ΔS, and ΔG of extraction process were studied and the numerical values of these parameters were calculated and discussed in details.