Microextraction by packed molecularly imprinted polymer followed by ultra-high performance liquid chromatography for determination of fipronil and fluazuron residues in drinking water and veterinary clinic wastewater

[Display omitted] •New method for FIP and FLZ determination by MEPS/ UHPLC-DAD.•MMIP was efficient and selective for FIP and FLZ aqueous samples.•MMIP presented high selectivity and recovery in drinking and wastewater.•MEPS/UHPLC/DAD method provided fast analyses in real water samples. A fast, efficient and safe method combining a low-cost lab-microextraction by packed sorbent-device and high-ultra-performance liquid chromatography with diode array detection was developed to determine fipronil and fluazuron residues in drinking water and veterinary clinic wastewater. The prepolymerization complexes of mesoporous molecularly imprinted polymer was studied by density functional theory calculations reaching ΔH = −26.7 kcal mol−1 and ΔG = −8.5 kcal mol−1, in which used fluazuron as template, methacrylic acid as monomer and acetonitrile as porogenic solvent. After, mesoporous molecularly imprinted polymer was properly characterized, demonstrating excellent selectivity to the studied analytes and high adsorbent capacity. After optimization, the better sample preparation conditions were: 75 µL of ultrapure water as washing solvent, 250 µL as methanol as eluent, 250 µL of sample at pH 7, two thaw-eject cycles and two times can be reused. After proper validation, the method was applied in the analysis of fipronil and fluazuron residues in drinking water and veterinary clinic wastewater and showed high reproducibility with relative recoveries of 98.58 ± 2.64% and 99.92 ± 1.43% for fipronil and fluazuron, respectively.