Analysis of Ochratoxin A in Malt Beverage Samples using Dispersive Liquid-Liquid Microextraction Coupled with Liquid Chromatography-Fluorescence Detection

摘要

A simple and economic procedure based on dispersive liquid-liquid microextraction has been applied to extract and pre-concentrate trace levels of ochratoxin A (OTA) in malt beverage prior to analysis using high performance liquid chromatography with fluorescence detection. The method was based on the formation of fine droplets of a water-immiscible extraction solvent in the sample solution using a water-miscible disperser solvent. The influences of various parameters such as the type and volume of extraction and disperser solvents, centrifuging time, sonication time, and salt concentration on the extraction efficiency of ochratoxin A were investigated. Under optimum conditions, the relative standard deviations for five replicates of 2 ng/ml of OTA were 3.4% as within-day and 6.2% as between-day precisions. The detection limit (S/N = 3) was 0.1 ng/ml and the mean recoveries of OTA from malt beverage samples at spiking levels of 0.5, 2, and 4 ng/ml were in the range of 104-108.2%.