Host guest inclusion complex/polymer-CNT composite for efficient determination of uric acid in presence of interfering species

Abstract

Monitoring uric acid (UA) level in human body is important to protect our body from serious diseases. A simple and efficient electrochemical sensor is fabricated for electrochemical sensing of UA in presence of interfering species: epinephrine (Ep) and tyrosine (Ty). The sensor is fabricated by drop-casting a thin layer of CNTs followed by electrodeposition of two successive thin layers of poly(L-methionine) (PMT) and 18-crown-6 (CW) over a glassy carbon (GC) surface; GC/CNT/PMT/CW. Each of the sensor components' unique property contributes in synergism to the current signal enhancement. CNTs and PMT offer large surface area, good electrical conductivity, and stability; crown ether allows good binding ability, stable supramolecular complexes, and excellent host-guest interaction. Infrared analysis is performed to confirm the formation of the inclusion complex between UA and CW. Voltammetry determination of UA in presence of Ep and Ty in human blood serum in the concentration ranges (0.04 to 40 μM), (0.04 to 40 μM), and (0.08 to 75 μM) is successfully achieved with low detection limits of 2.7 nM, 2.3 nM and 6.3 nM, respectively. Practical application of the GC/CNT/PMT/CW sensor is efficiently assessed in human serum samples for UA determination with acceptable recoveries, excellent anti-interference ability and long-term stability. • Successive layers of CNTs, PMT and CW are used to fabricate a UA sensor. • The sensor determines UA in presence of Ep and Ty with low detection limits. • The DL and sensitivity for UA sensing in serum are 2.2 nM and 2.123 μA/μM. • The sensor components provide improved conductance and electroactive area. • The sensor shows resistance to interference from several species and excellent recovery.