LAUSR

Abstract Herein, a method based on microextraction in packed sorbent (MEPS) with polythiophene (PTh) as adsorbent material and HPLC-DAD was developed. PTh was synthesized by oxidative method and used to extract progesterone (PGN), prednisolone (PRE) and estradiol (ESD) from bovine milk samples. The adjusted chromatographic conditions were: C18 column (150 mm × 4.60 mm, 5 µm), mobile phase: methanol: acetonitrile (55: 45, v/v) with flow rate at 0.85 mL min−1 and temperature at 40 °C. The main parameters that affecting the sample preparation were optimized: washing solvent, eluent solvent, sample pH, volume sample, mass of sorbent, and cycles of aspersion/dispersion. The method presented linearity in the linear range between 16 and 1200 ng mL−1 and correlation coefficients (r) ≥ 0.99 for the three analytes with recoveries greater than 85%. The validated method was used successfully for the analyses of bovine milk samples.