Response surface methodology optimized dispersive liquid-liquid microextraction coupled with UV-Vis spectrophotometry for determination of quinine

Dispersive liquid-liquid microextraction (DLLME) followed by UV-Vis spectrophotometry was applied for extraction/preconcentration and determination of trace levels of quinine (QN). Chloroform and methanol were chosen as the extraction solvent and the disperser solvent, respectively. A central composite design (CCD) was applied to optimize the effective parameters of DLLME including volume of extraction solvent, pH, and salt concentration. The optimal conditions were obtained as 160 mu L for the volume of extraction solvent, 9.88 for pH, and 2.2% (w/v) for salt concentration. The linear dynamic range (LDR) was 25-700 mu g L-1 with a correlation coefficient of 0.994. The limit of detection (LOD) and relative standard deviation (RSD) were 14.71 mu g L-1 and 1.13%, respectively. The method was successfully applied for the determination of QN in real samples and satisfactory relative recoveries (101.51-108.02%) were obtained.