Nanomolar determination of 4-nitrophenol based on a poly(methylene blue)-modified glassy carbon electrode

Abstract

A poly(methylene blue)-modified glassy carbon electrode (PMB/GCE) was fabricated by electropolymerisation of methylene blue on a GCE and further utilized to investigate the electrochemical determination of 4-nitrophenol (4-NP) by cyclic voltammetry (CV), differential pulse voltammetry and chronocoulometry. The morphology of the PMB on GCE was examined using a scanning electron microscope (SEM). An oxidation peak of 4-NP at the PMB modified electrode was observed at 0.28 V, and in the case of bare GCE, no oxidation peak was observed, which indicates that PMB/GCE exhibits a remarkable effect on the electrochemical determination of 4-NP. Due to this remarkable effect of PMB/GCE, a sensitive and simple electrochemical method was proposed for the determination of 4-NP. The effect of the scan rate and pH was investigated to determine the optimum conditions at which the PMB/GCE exhibits a higher sensitivity with a lower detection limit. Moreover, kinetic parameters such as the electron transfer number, proton transfer number and standard heterogeneous rate constant were calculated. Under optimum conditions, the oxidation current of 4-NP is proportional to its concentration in the range of 15-250 nM with a correlation coefficient of 0.9963. The detection limit was found to be 90 nM (S/N = 3). The proposed method based on PMB/GCE is simple, easy and cost effective. To further confirm its possible application, the proposed method was successfully used for the determination of 4-NP in real water samples with recoveries ranging from 97% to 101.6%. The interference due to sodium, potassium, calcium, magnesium, copper, zinc, iron, sulphate, carbonate, chloride, nitrate and phosphate was found to be almost negligible.

Electrochemical Sensor Based on Carbon Nanotubes for the Simultaneous Detection of Phenolic Pollutants

“…The above results show that the SWCNT modified electrodes can efficiently catalyze the electrocatalytic oxidation of different phenolic compounds at different electrode potentials. The SWCNT facilitates the electron‐transfer process at the modified electrodes for the oxidation of phenolic compounds 35, 36. It is worthy to notice that the CVs of the electrochemical oxidation of the phenolic compounds at the GC/SWCNT electrode were stable and that no obvious changes of the peak potentials and currents were observed over repetitive cycles.…”

Nanomaterials-based electrochemical detection of chemical contaminants

“…156 The proposed sensor was applied to detect p-nitrophenol in real water samples using a DPV method. 156 The proposed sensor was applied to detect p-nitrophenol in real water samples using a DPV method.…”

A highly sensitive metronidazole sensor based on a Pt nanospheres/polyfurfural film modified electrode

“…[23][24][25][26][27][28][29][30][31][32][33] Polymer-modied electrodes have attracted great attention in sensing applications. [34][35][36][37][38][39][40][41] In particular, the strategy of electropolymerization is to immobilize a polymer lm onto an electrode surface with multiple active sites and advantages of rapid synthesis, controllable lm thickness, exible charge transport and permeation characteristics by easily adjusting the electrochemical parameters. 42,43 Previously, we have successfully prepared a polyfurfural lm modied glassy carbon electrode (GCE) by a one-step electropolymerization , which exhibits excellent electrocatalytical activity to the reduction of the nitro group in hexatomic aromatic compounds 44,45 due to the promoted electron transfer by the conjugated p-electron backbones of polyfurfural lm.…”