Simultaneous determination of strobilurin fungicides residues in bean samples by HPLC-UV-AD using boron-doped diamond electrode

Abstract

The aim of this paper was the development of a method for the determination of six strobilurins (fungicides) using boron-doped diamond (BDD) electrode with amperometric detection (AD) homemade coupled to high performance liquid chromatography (HPLC/UV–Vis). HPLC separation of fungicides was performed in a C18 reverse phase column using both UV and AD detectors at 200 mn and 1.9 V, respectively. The linear range for each strobilurin was from 5 to 15 mg L−1 and the correlation coefficients for all the compounds were above 0.997. Both detectors presented adequate detectability (LOD ranging from 1.33 to 1.57 μg kg−1) respecting the limits pre-established by regulatory agencies. The method was validated presenting good values of recovery and accuracy. In the spiked samples the recoveries ranged from 61.6% (trifloxystrobin) to 98.8% (azoxystrobin) for UV and 62.3% (trifloxystrobin) to 95.2% (azoxystrobin) for AD. In blanks spikes the recovery varied from 77.8% (picoxystrobin) to 88.4% (kresoxim-methyl) for UV and 76.7% (picoxystrobin) to 87.1% (dimoxystrobin) for AD. The method showed good precision (RSD < 10%). The results obtained by amperometric and UV detections were statistically comparable. Seven bean samples were analyzed to detect fungicide residues.