SPE columns with pH-sensitive molecularly imprinted polymer toward gentamicin

Molecularly imprinted polymers with affinity toward gentamicin were synthesised according to the principles of green chemistry, in an aqueous solution at ambient temperature. Polyacrylic acid, a polymer that changes chain conformation depending on the pH, was incorporated into the polymer network. This approach allowed the development of a material regeneration method using changes in the alkalinity of the solution. The conditions of static sorption (1.45 mg/g and 0.69 mg/g for MIP and NIP, respectively, pH 5.5) and desorption (1.04 mg/g and 0.64 mg/g for MIP and NIP, respectively, pH 9.5, 4 °C) were selected. Next, the obtained polymers were placed in solid-phase extraction columns and their performance was optimised. Bed conditioning (1 × 24 h, pH 9.5, 4 °C; 2x continuous mode pH 9.5, 4 °C; 1 × 15 min pH 5.5, 22 °C) sorption (1-5 h) and desorption (4 × 30 min) were established. In the presence of amoxicillin and norfloxacin, selectivity in tap water was determined (selectivity factor in the range of 3.03-3.07, respectively).