Molecularly imprinted polymer-based solid-phase microextraction fiber coupled with molecularly imprinted polymer-based sensor for ultratrace analysis of ascorbic acid.

Clinical manifestations owing to ascorbic acid deficiency demand an easy-to-use, rapid, robust and inexpensive technique, which can measure serum ascorbic acid at ultratrace level to attend the problem of hypovitaminosis C and acute cases of scurvy. In the present work, a novel molecularly imprinted polymer (MIP)-coated solid-phase microextraction (SPME) fiber that could be coupled to a complementary MIP-sensor was prepared with ascorbic acid as a template molecule. The characteristics and applications of this fiber were investigated. The same MIP receptor for both SPME and the corresponding sensor was able to enhance the preconcentration of analyte substantially so as to attain the stringent level of sensitivity in highly diluted aqueous, blood serum and pharmaceutical samples. The extraction yield of ascorbic acid (AA) with the MIP-coated fiber was found to be quantitative (detection limit 0.0396 ng mL(-1), RSD=2.3%, S/N=3) in aqueous samples without any problem of non-specific false positive results and cross-reactivity.