Selective and invisible separation and determination of Rhodamine B in diverse industrial samples using aqueous biphasic switchable hydrophilicity solvent-like based microextraction method

Abstract

An effective and selective aqueous biphasic switchable hydrophilicity solvent-like based microextraction method (ABSHS-ME) combined with UV–vis spectrophotometry was established for the first time to monitor Rhodamine B (RhB) at 550 nm in soaps, lipsticks, anti-freezes and match tips. RhB was extracted firstly as its invisible form into immiscible hydrophobic phase and then converted to its UV–vis active form using acidified ethanol. The essential extraction parameters (pH, SHS volume, and vortex time) were optimized by Box-Behnken Design of Response Surface Methodology. Quadratic model with R2 = 0.9893 was found as favourable chemometric design for ABSHS-ME method. Preconcentration factor was obtained to be 25. Effect of matrix ions and dyes were examined in detail. 7 and 24 µg/L of Rhb were determined for limit of detection and limit of quantitation, respectively. RhB was determined linearly between 24 and 2500 µg/L. Relative standard deviations were lower than 7 %. ABSHS-ME method was validated determining the RhB concentrations of industrial samples with analyte addition-recovery tests. RhB contents of the real samples analyzed were found between 0.26–1.07 µg/g and 1.53–4.73 µg/mL with recovery values ranging from 95 to 101 %. The environmentally friendly index of the method was evaluated using the new generation AGREE tool.