Study on the preparation of molecular imprinted polymer for analysis of N-phenylglycine in human urine.

N-phenylglycine (NPG) in human urine could be an important biomarker for predicting cancers, but its detection has difficulty due to its low abundance in urine. Herein, we report a molecular imprinted polymer (MIP) method to efficiently recognize NPG in urine. The MIP was prepared by precipitation polymerization, adopting NPG as the template, acrylamide (AM) as functional monomer, trimethylpropane triacrylate (TRIM) as crosslinking agent, and acetonitrile as porogen. The specificity and selectivity of MIP towards NPG in human urine were determined by comparing MIP's adsorption to the NPG and N-crotonylglycine (NTG) under the same conditions. The result ß = QMIP-NPG/QMIP-NTG = 4.7 indicated the satisfactory specificity and selectivity. Parameters affecting the extraction efficiency were further optimized. Under the optimum conditions, the linear range, limit of detection, and limit of quantification of NPG were 0.5-100 mg∙L-1, 1.6 × 10-2 mg∙L-1, and 5.5 × 10-2 mg∙L-1, respectively. Recoveries of NPG in human urine were in the range of 84.7-100.0% with RSDS of 3.8-10.8%. The developed method demonstrated superior selectivity to the target analyte, which can be applied to separate and enrich the NPG from urine samples.

Facile synthesis of molecularly imprinted polymers for selective extraction of tyrosine metabolites in human urine.

In this study a method is developed for quantitative analysis of three potential biomarkers, including 4-hydroxyphenyl acetic acid (PHPAA), 4-hydroxyphenyl lactic acid (PHPLA) and 3,4-hydroxyphenylpropionic acid (PHPA), in human urine. Molecular imprinted polymers (MIPs) as the sample clean up materials were applied to selectively extract these tyrosine metabolites, followed by precise detection using ultra-high performance liquid chromatography coupled with a fluorescence detector (UHPLC-FLD). The MIP was prepared by precipitation polymerization adopting PHPAA as the template molecule, 1-vinylimidazole (1-vinyl) as functional monomer, trimethylolpropane triacrylate (TRIM) as crosslinker, 2-methylpropionitrile (AIBN) as initiator and acetonitrile as a porogen. The molecular recognition properties and selectivity of MIPs were systematically evaluated, of which results demonstrated high selectivity for three analytes in human urine. Parameters affecting the extraction efficiency were further optimized. Under the optimum conditions, the limits of detection of PHPAA, PHPLA, and PHPA were 1.8 × 10-4, 4.7 × 10-5 and 5.8 × 10-5 mmol L-1, respectively, and the recoveries were in the range of 75.7%-110.3%. The method described here provided insights into the future development of materials for highly efficient and selective enrichment of targeted substances.