Salicylic acid assisted cloud point extraction at room temperature: Application for preconcentration and spectrophotometric determination of molybdenum(VI)

Abstract

In this study, a novel and rapid procedure for the salicylic acid assisted cloud point extraction of molybdenum(VI) is presented. Preconcentration of the substrate has been suggested prior to its spectrophotometric determination method. The method involves the complexation of Mo(VI) with 6,7-dihydroxy-4-methyl-2-phenylbenzoryrylium chloride (DHMPhB), followed by extraction of the complex into micellar phase of Triton X-100. The cloud point phenomenon at room temperature was activated by formation of salicylic acid. This reaction prevents the formation of hydrogen bonds between surfactant and water molecules and causes immediate formation (<1 min) of the surfactant-rich phase. The calibration curve for Mo(VI) was obtained in the concentration range of 0.16–1.8 μg mL−1 under optimized conditions (pH 2; 1·10−4 M DHMPhB; 0.1 M NaSal; 0.05 M H2SO4 and 1% (v/v) Triton X-100). The limit of detection is 0.05 μg mL−1. The method was successfully used to determine trace quantities of Mo(VI) in water samples, the rose hips and pharmaceuticals with favorable results.