Hollow dummy template imprinted boronate-modified polymers for extraction of norepinephrine, epinephrine and dopamine prior to quantitation by HPLC

The authors describe boronate-modified hollow dummy template imprinted polymers (B-hDIPs) for selective and sensitive extraction of the catecholamines norepinephrine (NE), epinephrine (E), and dopamine (DA) from urine samples prior to their detection by HPLC with UV detector. The B-hDIPs were prepared by using (a) nano-TiO2 as the sacrificial support, (b) 3-carboxyphenylboronic acid (CPBA) as the boronate-affinity functional monomer, and (c) catechol which acts as dummy template. The nano-TiO2 can be etched off by using hydrofluoric acid to form the hollow imprint. The main advantages of using such hollow polymers arise from their controllable hole structure which favors template removal and fast mass transfer. The B-hDIPs material was characterized by FT-IR, transmission electron microscope, dynamic light scattering, X-ray photoelectron spectrum, and thermal gravimetric analysis. The effects of imprinting conditions, sample pH, sample flow rate, adsorbent amount, selectivity and competitive capacities were investigated. Under optimal conditions, the limits of detection for the catecholamines are in the range from 15 to 47 ng mL(-1). The method was successfully applied to their determination of NE, E, and DA in spiked urine, with recoveries ranging from 63.4 to 106.2%.