Determination of flumequine and oxolinic acid in sediments and soils by microwave-assisted extraction and liquid chromatography-fluorescence Original Research Article

A method is reported for the determination of the quinolones oxolinic acid and flumequine in aquatic sediments and agricultural soils. The analytes are extracted by liquid–liquid partitioning between a sample homogenated in an aqueous buffer solution and dichloromethane. Microwave-assisted extraction (MAE) was tested to improve the speed and efficiency of the extraction process. The parameters affecting the efficiency of MAE, such as irradiation time and temperature, were studied. The clean-up consists of back-extraction in 1 M sodium hydroxide. The determination is carried out by reversed phase liquid chromatography on an octyl silica-based column and fluorimetric detection. The optimised method was applied to the analysis of two sediments and one agricultural soil spiked with the analytes. The absolute recovery rates for the whole process range from 79% to 94% (RSD 3–7%), and detection limits are in the low μg kg−1 level.