Metal organic framework/clay composite for micro-dispersive solid-phase extraction of sulfonamides and penicillins in milk, and synthetic urine solution coupling with HPLC/DAD detection

In this study, composite as a copper-containing metal-organic framework with montmorillonite (MMT) clay was synthesized and applied as an adsorbent for micro-dispersive solid-phase extraction (mu-dSPE) of sulfonamides (SAs) and penicillins (PENs). The synthesized composites including different content of MMT were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface area, and thermogravimetric analysis. The determination of antibiotics was performed by high-performance liquid chromatography/diode array detection (HPLC/DAD) using C18 column as stationary phase, 0.1 % trifluoroacetic acid in water, and acetonitrile as mobile phase in gradient mode and detection at 270 nm for SAs and 230 nm for PENs. The as-synthesized composites were examined for their adsorption ability towards target antibiotics. The optimized parameter conditions were 10 mg of adsorbent, 5 mL of sample solution at pH 4, 10 min stirring by vortex, 1 mL of acetonitrile:methanol (1:1) as eluent solvent, and 5 min as elution time. Under optimized conditions, the proposed method presented good linearity from 0.5 to 400 mu g/L for SAs and from 1 to 400 mu g/L for PENs with coefficients of determination (r(2)) >= 0.9947, low limit of detections from 0.10 to 0.15 mu g/L for SAs and 0.30 to 1.50 mu g/L for PENs, acceptable repeatabilities less than 3.26 % for both groups and good recoveries from 82.3 % to 116.4 % with relative standard deviations less than 3.9 % for both groups in the spiked milk samples and synthetic urine solution. The developed mu-dSPE method following HPLC/DAD has been successfully applied to the determination of SAs and PENs milk samples and synthetic urine solutions.