A novel enzyme-less uric acid voltammetric sensor based on highly selective nano-imprinted polymer synthesized utilizing [tetrabutyl ammonium] plus -[urate]- ion-pair complex as template

Uric acid is well known as a critical biological compound and its concentration level in biological fluids such as urine and plasma is correlated to some serious disorders. The preparation of imprinted polymer for this com-pound poses challenges because of its highly hydrophilic characteristic, disabling its dissolving in the rationally applied low dielectric solvents. Herein, the uric acid-selective nano-sized molecularly imprinted polymer (nano-MIP) was synthesized utilizing the aprotic solvent of chloroform. This was executed by introducing an ion pair complex compound of [tetrabutyl ammonium]+-[urate] which was created in an aqueous media followed by its extraction in an immiscible solvent of chloroform. The extraction condition was optimized to maximize the efficiency of uric acid extraction. The polymeric nanoparticles were utilized as the modifying agent of a carbon paste electrode (CPE). The nano-MIP/CPE electrode response to uric acid was excellently higher than both the non-imprinted polymer-modified CPE (nano-NIP/CPE) and CPE, demonstrating the presence and well -functioning of selective sites within the MIP nanoparticles. The responses of the NIP/CPE and CPE electrodes to uric acid were found to be the same which is a good indication of the absence of non-selective uric acid up -taking by the MIP material. The optimized sensor response to uric acid was linear in the concentration range of 0.6 to 10.0 mu M. The detection limit was estimated to be 0.03 mu M (3S/N). The fabricated sensor showed excellent selectivity against uric acid's similar compounds and it was successfully applied for uric acid determination in urine samples.

Automated summary

In this study, a uric-acid selective nano-sized molecularly imprinted polymer (nano-MIP) was successfully synthesized and applied for uric acid determination. The MIP exhibited good solubility in low dielectric solvents and showed higher response to uric acid compared to non-selective materials.