A reversed-phase high-performance liquid chromatography method combined with matrix solid-phase dispersion extraction for the determination of teflubenzuron, lufenuron and bifenthrin residues in lyophilized coconut water

An extraction method based on matrix solid-phase dispersion was developed to determine lufenuron, bifenthrin and teflubenzuron in lyophilized coconut water using liquid chromatography with UV–vis absorbance detector. The best results were obtained using 0.5 g of lyophilized coconut water, 2.5 g of C18-bonded silica as dispersant sorbent and acetonitrile (20 mL) as eluting solvent. The method was validated using lyophilized coconut water samples fortified with pesticides at three concentration levels (0.25, 0.5 and 1.0 mg kg−1). Average recoveries (3 replicates) ranged from 74 to 116%, with relative standard deviations between 0.4 and 9.4%. Detection limits for lyophilized coconut water ranged from 0.04 to 0.05 mg kg−1 and quantification limit was of 0.1 mg kg−1.