Molecularly imprinted solid phase microextraction fiber for trace analysis of catecholamines in urine and serum samples by capillary electrophoresis

A selective and flexible monolithic moleculary imprinted polymer (MIP) fiber was developed in batch for solid phase microextraction (SPME) of catecholamines (CAs), i.e., dopamine (DA), epinephrine (E) and norepinephrine (NE), and coupled with capillary electrophoresis (CE) for trace analysis of urine and serum samples. The polymer fiber was synthesized in-situ simply using a flexible capillary as a mold and the polymerization protocols and SPME experimental conditions were examined in detail. The reproducibility of fiber to fiber fabrication (n=5) was in range of 5.9–9.8% for three CAs. The fiber also shows high stability without any deterioration of extraction performance after 30 times use. Under the established optimum conditions, the limits of detection for DA, E, and NE were 7.4, 4.8, and 7.1 nmol L−1, respectively, with the enhancement factor over 100 after MIP-SPME. The specific selectivity to three CAs was discovered with the developed MIP fibers compared with non-imprinted polymer (NIP) fiber. Finally, the MIP fibers were successfully applied for selective extraction of CAs in urine and serum samples with the relative recoveries ranging from 85% to 103%. The fabricated MIP-fibers were promising in preparation of biological samples in batch followed by CE–UV detection.