Fluoroquinolones in soils: Assessment of extraction methods

摘要

The extraction of six fluoroquinolones from agricultural soils with different physicochemical characteristics (pH, texture and organic carbon content) has been investigated. Different solvents, consisting of hydroorganic mixtures, have been tested, and basic buffer solutions, with either acetonitrile or acetone, have proved to be suitable extraction solvents. Conventional mechanical shaking and microwave-assisted extraction techniques have been evaluated, and mechanical shaking has been selected. Recovery rates from freshly spiked (overnight) soils ranged from 65 to 90%, depending on the quinolone. No relevant dependence on soil characteristics has been observed. The effect of ageing on the extraction behaviour of fluoroquinolones has also been considered. In comparison with freshly spiked soils, extractions from residues aged for some months have resulted in about 20-25% lower recovery rates.