S(O)MWCNT/modified Carbon Paste – A Non‐enzymatic Amperometric Sensor for Direct Determination of 6‐Mercaptopurine in Biological Fluids

Abstract

In this study, carbon paste electrode (CPE) modified with strongly oxidized MWCNT (S(O)MWCNT) was developed as an efficient, economical, electrochemical sensor for the detection of 6‐mercaptopurine (6MP) with antineoplastic and immunosuppressive activities. However, this cytotoxic anticancer drug is associated with adverse side‐effects; hence 6MP determination becomes crucial. Drop‐cast‐coating was an effective strategy in the fabrication of S(O)MWCNT/MCPE to increase surface area. Electrochemical measurements were performed using cyclic voltammetry (CV) and amperometry. Electrochemical Impedance Spectroscopy (EIS), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X‐ray (EDX) elucidated surface characteristics. With S(O)MWCNT's good conductive ability, we achieved rapid electron transfer that amplified 6MP anodic signal by 3.8 folds higher compared to bare CPE. Additionally, great consonance between CPE loaded with S(O)MWCNT yielded superior current response with decreased activation energy compared to S(O)MWCNT/modified glassy carbon electrode (S(O)MWCNT/MGCE). Under optimal conditions S(O)MWCNT/MCPE displayed a wide‐single‐linearity range from 1.0 to 100.0 μM with an excellent detection limit of 0.24 μM during amperometric quantification for the first time. It also exhibited good selectivity, after a series of common physiological interferents’ assessment. As a part of proof‐of‐concept, the proposed sensor was investigated in 6MP fortified human fluids, and the satisfactory recoveries obtained authenticated S(O)MWCNT/MCPE's accuracy and reliability for practical applicability.

Electrodetermination of Gallic Acid Using Multi‐walled Carbon Nanotube Paste Electrodes and N‐Octylpyridinium Hexafluorophosphate

“…In addition, they display notable advantages such as commercial availability, minimization of phenol polymerization and electrode corrosion, and high overpotential for oxygen production [21]. However, modification of their surface is often reported in the literature, preventing electrode fouling and enhancing process efficiency and sensitivity [22][23][24][25][26][27][28].…”

A polyoxometalate based electrochemical sensor for efficient detection of L-cysteine

“…Generally, the enzyme electrochemical sensors have advantages of high sensitivity and selectivity, but they are not very stable, as the enzyme can be easily influenced by pH, temperature, humidity and toxic chemicals [9][10][11]. On the contrary, nonenzymatic electrochemical sensors are facile, cost-effective, and environmentally friendly [12][13][14]. Therefore, to develop more ideal L-cys sensors for industrial applications, many researchers turn to exploring nonenzymatic electrochemical sensors.…”

“…Therefore, it is necessary to modify the ITO electrode as the substrate. The modified electrode has a large surface area, electrocatalytic activity and high sensitivity [9][10][11][12]. Because the chemically modified electrode method is simple, fast, and reusable, this method is widely used [13,14].…”

Amorphous Carbon Film with Self‐modified Carbon Nanoparticles Synthesized by Low Temperature Carbonization of Phenolic Resin for Simultaneous Sensing of Dopamine and Uric Acid

“…Sensors are the product of the mutual penetration and multiple disciplines [1]. Because of high sensitivity and fast analysis speed, sensors are developing rapidly in detecting physiological problems related to human health [2][3][4][5]. Dopamine (DA) and uric acid (UA) have been known to play a vital role in human metabolic functions and behaviour [6].…”