Simultaneous determination of ten fluoroquinolone residues in organic fertilizers by QuEChERS and high performance liquid chromatography-tandem mass spectrometry

Abstract

The analysis of veterinary drugs in organic fertilizers is crucial for an assessment of their potential risks to microbial communities in soils and to human health. A method has been developed for the simultaneous determination of ten fluoroquinolones in organic fertilizers by using the QuEChERS method coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with disodium ethylenediaminetetraacetic acid (Na2EDTA)-McIlvaine buffer (pH=4.0) and acetonitrile. The target compounds were separated on an Atlantis T3 C18 column (250 mm×4.6 mm, 5 μm) with a mobile phase of 0.2% (v/v) formic acid in acetonitrile and analyzed in the multiple reaction monitoring (MRM) mode via electrospray ionization (ESI). Ten fluoroquinolones were quantified by an internal standard method. The calibration curves of the ten fluoroquinolones exhibited good linearity over the range of 10-500 μg/kg, and the correlation coefficients were above 0.9930. The limits of detection were 0.5-2.5 μg/kg; the limits of quantification were 1.7-8.3 μg/kg. The analytical method was successfully applied in a survey of veterinary drug contamination in nine compost samples. The average recoveries were 82.5%-117.1%, with relative standard deviations of 3.4%-10.2%. The method is accurate, reliable, and sensitive and supports the simultaneous detection of various veterinary drug residues. Therefore, this method can provide a basis for the risk assessment of veterinary drugs in organic fertilizers.