Development of a highly sensitive and selective hyphenated technique (molecularly imprinted micro-solid phase extraction fiber–molecularly imprinted polymer fiber sensor) for ultratrace analysis of folic acid

A simple polymerization strategy is reported in this work which allows molecularly imprinted polymeric fiber (monolith) fabrication for direct use in sensing devices. This is advantageous for achieving higher degree of enrichment of target analyte (folic acid) from the complex matrices of real samples, without any surface fouling, cross-reactivity, and non-specific (false-positive) contributions. In order to measure serum folic acid at ultratrace level to detect spina bifida, a neural tube defect in mother, and other acute cases of proteomic diseases, the hyphenation between molecularly imprinted micro-solid phase extraction fiber and a complementary molecularly imprinted polymer–carbon composite fiber sensor has been found quite efficient. The primitive diagnosis of many chronic diseases is feasible by estimating folic acid as biomarker, with the detection limit as low as 0.0036 ng mL−1 (relative standard deviation = 0.13%, signal/noise = 3) in human blood serum.