Response surface methodology optimization of supramolecular dispersive liquid-liquid microextraction-solidified floating organic drop of brilliant green and its spectrophotometric determination

A simple supramolecular dispersive liquid-liquid microextraction-solidified floating organic drop (SMDLLME-SFOD) method was developed for the separation and preconcentration of brilliant green (BG) before its spectrophotometric determination. The method is based on the extraction of ion-pair of BG with sodium dodecyl sulfate into the coacervates made up of decanoic acid reverse micelles in the tetrahydrofuran-water mixture. The influence of the effective parameters on the extraction of BG was investigated and optimized using response surface methodology. Under the optimized conditions, the calibration graph was linear in the range of 1.0–50.0 μg L⁻¹ of BG. The limit of detection (LOD) and limit of quantification (LOQ) were 0.28 μg L⁻¹ and 0.94 μg L⁻¹, respectively. The repeatability expressed as the relative standard deviation for six replicate measurements at 5.0 μg L⁻¹ BG was 3.6%. The method was successfully applied to the extraction and determination of BG in different water and fish samples.