Application of ionic liquid-based dispersive liquid-liquid microextraction for the analysis of ochratoxin A in rice wines

A novel and rapid ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) method combined with liquid chromatography and a fluorescence detector for the analysis of ochratoxin A in rice wines is presented. The following parameters were systematically investigated: type and volume of ionic liquid, volume of dispersive solvent, salt addition, sample pH, and vortex time. Rice wine samples were first diluted to 18% alcohol with deionized water, and the pH was adjusted to 3.0. A DLLME procedure was followed that included IL ([HMIM][PF6]) and ethanol as the extraction and dispersive solvents, respectively. Under the optimized experimental conditions, good linearity was obtained with a correlation coefficient (r) of 0.9998 and a limit of detection (LOD) of 0.04 μg L−1. The recoveries ranged from 75.9% to 82.1% with an RSD below 10.4%. The proposed method was successfully applied to analyse OTA samples from several rice wine brands collected in Guangdong province, China.