Boronic acid functionalized polymeric microspheres for catecholamine isolation

In this study, 3-aminophenyl botanic acid functionalized-poly(3-chloro-2-hydroxypropyl methacrylate) [APBA functionalized-poly(HPMA-C1)] microspheres were prepared and characterized as a new alternative sorbent for catecholamine isolation. Chloropropyl group containing poly(HPMA-C1) microspheres were synthesized in spherical gel form with a suspension polymerization technique, and it is followed by the APBA conjugation to the poly(HPMA-CI) microspheres through amide bond formation. Afterwards, for the characterization of the prepared microspheres, SEM images were taken and FTIR analysis was performed. Furthermore, to determine APBA content of prepared microspheres, nitrogen analysis was performed and the amount of APBA was calculated as 94.6 mg APBA/g microsphere. The average size of the APBA functionalized-poly(HPMA-CI) microspheres was calculated as 205 35 pm. The reversible catecholamine (dopamine, epinephrine and norepinephrine) binding behavior of the APBA functionalized-poly(HPMA-C1) and poly(HPMA-CI) microspheres was investigated in batch fashion type. In the reversible catecholamine binding experiments, the maximum equilibrium binding was obtained at pH 8.5 which is very close to the plCa of boronic acid, therefore all the experiments were carried out at this pH. While no-significant non-specific binding was observed onto the non-functionalized microspheres, the maximum catecholamine binding capacities of the APBA functional ized-poly(H PMA-CI) microspheres were found as 61 mg, 7 mg and 8 mg per gram of microsphere for dopamine, epinephrine and norepinephrine, respectively. All three of the catecholamines were released from the microspheres with the yields higher than 90% by weight. The obtained results indicated that APBA functionalized-poly(HPMACI) microspheres are promising sorbents that can be used for the efficient isolation of catecholamines. (C) 2014 Published by Elsevier B.V.