Poly(crystal violet) modified pencil graphite electrode sensor for the electroanalysis of catechol in the presence of hydroquinone

Development of a Diethylcarbamazine Citrate‐Based Electrochemical Sensor for Quick and Affordable Detection of Sulfadiazine and Uric Acid in Environmental Monitoring

The widespread use of antibiotics like sulfadiazine (SDZ) in various industries has raised environmental and health concerns due to their potential for bioaccumulation and the subsequent effects on human health and the environment. Diethylcarbamazine citrate (DCZ), a well‐established antifilarial drug, has yet to be explored as a sensing agent despite its extensive use. This study proposes a cost‐effective and efficient method for detecting SDZ and Uric acid (UA) using a DCZ‐modified carbon paste electrode (poly‐DCZ/MCPE). The poly‐DCZ film is synthesized via cyclic voltammetry (CV) on the carbon paste electrode surface, demonstrating excellent electrocatalytic activity for SDZ and UA detection at pH 7.4. The diffusion‐controlled electrode process is observed with a lower limit of detection (LOD) and limit of quantification (LOQ) for SDZ as 3.8×10−9 M and 12.94×10−9 M respectively. For UA, LOD and LOQ were found to be 6.291×10−9 M and 20.97×10−9 M respectively at the poly‐DCZ/MCPE. Notably, the sensor exhibits simultaneous detection capabilities for SDZ and UA by CV and differential pulse voltammetry (DPV) methods, addressing the need to monitor antibiotic residues in aquatic ecosystems and animal‐derived products.

An ultrasensitive electrochemical platform based on copper oxide nanoparticles and poly (crystal violet) for the detection of brilliant blue FCF from soft drinks

In this study, a highly sensitive and quick electrochemical platform based on poly (crystal violet) film and copper oxide nanoparticles for the detection of brilliant blue FCF from various soft beverages was developed. The synthesized copper oxide nanoparticles were investigated with Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. Further, crystal violet was electropolymerized on the surface of the carbon paste electrode modified with copper oxide nanoparticles. The electrochemical properties of poly (crystal) violet/copper oxide nanoparticles modified carbon paste electrode were assessed through the utilization of cyclic voltammetry and electrochemical impedance spectroscopy. Furthermore, the signal towards the oxidation of brilliant blue was examined using the differential pulse voltammetry method. Under ideal experimental conditions, the peak current exhibited a linear relationship with the brilliant blue concentration within the range of 0.01-1.00 nmol/L, with a sensitivity of 294.55 µA nmol/L cm-2 and a significant detection limit of 3 pmol/L. In the presence of other dyes and other food additives, the developed platform showed greater selectivity in detecting brilliant blue. The reliability of the designed platform was demonstrated by the 99.19 - 100.67 recovery percentage for the identification of BB in various soft drink samples.

Conducting dyes as electro-active monomers and polymers for detecting analytes in biological and environmental samples

Currently, electrochemical sensors are regarded as an efficient tool for the biological and environmental sensing. Electrochemical sensors, such as voltammetric, amperometric, and impedimetric sensors, have gained great attention due to their simplicity, sensitivity, and selectivity. The performance of these electrochemical sensors could be enhanced by surface engineered nano/micro structured materials with conducting dyes/redox species. In this review, a great focus has been put on the redox-active dyes because of their electronic, optical, electrochromic, and conductivity properties. The mechanisms of oxidation and subsequent polymerization of different redox-active dyes at the surface of electrodes have been studied. Additionally, their role in catalyzing the oxidation or reduction of the target analytes at the surfaces of electrodes has also been highlighted. The redox-active dyes were used as electrochemical probes for detecting various analytes in biological and environmental samples. Overall, redox-active dyes are considered promising conducting polymers for the assessment of many analytes such as drugs, pesticides, surfactants, and heavy metal ions.

A novel, extreme low-cost poly (Erythrosine) modified pencil graphite electrode for determination of Adrenaline

A simple, novel, and less cost yellow (Erythrosine) modified pencil graphite electrode (Po-ERY/MGPE) was successfully fabricated via electropolymerization method using cyclic voltammetric techniques. The fabricated Po-ERY/MGPE opted as a sensor for the detection of Adrenaline (ADR) in 0.2 M PBS (7.4 pH). This reported senor displayed excellent electrocatalytic activity, increased sensitivity, high stability, superior electron transfer kinetics in the oxidation of ADR once relative to BGPE. The significance of pH, scan rate, and impact of concentration was assessed at the sensor. As per the pH and scan rate study, redox routes carry the same number of electrons and protons, and electro-oxidation of ADR was adsorption controlled respectively. The LOD of ADR was found to be 0.499 µM. The DPV data indicate that there is a significant peak divergence among ADR and uric acid (UA) which could make it easier to determine them alone and simultaneously on the sensor. The described method has been employed for the determination of ADR in injection sample. Good recovery values indicate the efficacy and applicability of the sensor in detecting ADR.

Electrochemical preparation and the characterizations of poly(3,5-diamino 1,2,4-triazole) film for the selective determination of pyridoxine in pharmaceutical formulations

This work describes the synthesis and characterization of a polymeric film of 3,5-diamino 1,2,4-triazole on a pencil graphite electrode for the selective sensing of pyridoxine (PY). The PGE was modified using the electropolymerization process by the potentiodynamic method. The polymerized electrode (PDAT/PGE) was characterized by IR, SEM, AFM, cyclic voltammetry, and electrochemical impedance spectroscopy. PY undergoes irreversible oxidation at 0.79 V on PDAT/PGE in phosphate buffer of pH 5. Using the differential pulse voltammetric technique (DPV), PY showed a linear range from 5 to 950 μM with a lower detection limit of 2.96 μM. The PDAT/PGE was applied for the analytical determination of PY in pharmaceutical tablets with good recovery.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11696-023-02777-5.

Highly sensitive square wave voltammetric method for determination of brucine in artificial urine samples based on choline chloride modified glassy carbon electrode

This paper demonstrates a highly sensitive Voltammetric sensor for determination of brucine (BRU) in artificial urine sample based on choline chloride modified glassy carbon electrode (ChCl/GCE). The simple and cost effective modification was performed by electrodeposition of choline chloride on glassy carbon electrode surface using cyclic voltammetry technique. The modified electrode surface was characterized by electrochemical, spectroscopic and microscopic imaging. The electrode yields a well-resolved peak current for the irreversible oxidation of brucine in the first scan and a pair of quasi-reversible peaks during the second scan. The CV study indicates that brucine undergoes an adsorption controlled electrochemical process with equal number of electrons and protons transfer on the ChCl/GCE. The SWV result shows that the reduction peak current of BRU at the ChCl/GCE was linear in the range of 0.001 μM-10 μM with limit of detection 8 × 10^-5 μM, limit of quantification 2.6 × 10^-4 μM and sensitivity of 116.4 μA/μM. The ChCl/GCE also showed an excellent selectivity, reproducibility and long-time stability towards the electrochemical reduction of Brucine. Moreover, the practical applicability of the fabricated ChCl/GCE was examined in order to determine BRU in artificial urine samples with recovery ranging from 95.5 to 102.7%. The validity of the developed method was confirmed by chromatographic techniques, high-performance liquid chromatography (HPLC) and the results obtained are consistent the HPLC method.

Synergetic effects of a poly-tartrazine/CTAB modified carbon paste electrode sensor towards simultaneous and interference-free determination of benzenediol isomers

Simultaneous and selective detection of dihydroxy benzene isomers by the synergistic effect of CTAB and tartrazine on a carbon paste electrode (poly-TZ/CTAB/MCPE) sensor by CV and DPV techniques.

Electrochemical sensor for the detection of adrenaline at poly(crystal violet) modified electrode: optimization and voltammetric studies

Herein, we report the electropolymerization of crystal violet (CRV) on a bare glassy carbon electrode (GCE) for the detection of adrenaline (AD). Electropolymerization parameters such as electrolyte pH, scan rate and monomer concentrations were optimized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The characterization of CRV and poly(crystal violet) (PCV) was done using FT-IR, UV-visible spectroscopy and EIS. More importantly, the charge transfer resistance (R_ct) and other EIS data recorded from the EIS of various forms of the poly(crystal violet) (PCV) modified glassy carbon electrode (GCE) in AD were used for identifying the best PCV modified electrode. Subsequent application of the electrode prepared at optimum conditions (PGCE) for AD detection using the square wave voltammetry (SWV) gave a limit of detection (LOD) of 2.86 μM over a linear range of 10.3-102.7 μM. This sensor also showed considerable stability, good AD recovery from the real sample (98.9%), and excellent reproducibility, making it a suitable analytical tool for AD detection at the micromolar level.

Electrochemical Detection of Dihydroxybenzene Isomers at a Pencil Graphite Based Electrode

In this work, an HB pencil electrode (HBPE) was electrochemically modified by amino acids (AAs) glycine (GLY) and aspartic acid (ASA) and designated as GLY-HB and ASA-HB electrodes. They were used in the detection of dihydroxybenzene isomers (DHBIs) such as hydroquinone (HQ), catechol (CC), and resorcinol (RS), by cyclic voltammetry (CV), and by differential pulse voltammetry. HBPE was characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. These three electrodes showed a linear relationship of current with concentration of DHBIs, and the electrochemical processes were diffusion controlled in all cases. In simultaneous detection, the limit of detection, based on signal-to-noise ratio (S/N = 3), for HQ, CC, and RS was 12.473, 16.132, and 25.25 μM, respectively, at bare HBPE; 5.498, 7.119, and 14.794 μM, respectively, at GLY-HB; and 22.459, 25.478, and 38.303 μM, respectively, at ASA-HB. The sensitivity for HQ, CC, and RS was 470.481, 363.781, and 232.416 μA/mM/cm², respectively, at bare HBPE; 364.785, 282.712, and 135.560 μA/mM/cm², respectively, at GLY-HB; and 374.483, 330.108, and 219.574, respectively, at ASA-HB. The interference studies clarified the suitability and reliability of the electrodes for the detection of HQ, CC, and RS in an environmental system. Real sample analysis was done using tap water, and the proposed electrodes expressed recovery with high reproducibility. Meanwhile, these three electrodes have excellent sensitivity and selectivity, which can be used as a promising technique for the detection of DHBIs simultaneously.

An experimental and theoretical approach to electrochemical sensing of environmentally hazardous dihydroxy benzene isomers at polysorbate modified carbon paste electrode

It is well known that, surfactants provide a neutral, positive and/or negative charge on the electrode surface by forming a monolayer, which in turn affects the charge transfer and redox potential during the electroanalysis process. However, the molecular level understanding of these surfactant-modified electrodes is worth investigating because the interaction of the analyte with the electrode surface is still unclear. In this report, we used quantum chemical models based on computational density functional theory (DFT) to investigate the polysorbate 80 structure as well as the locations of energy levels and electron transfer sites. Later, the bare carbon paste electrode (bare/CPE) was modified with polysorbate 80 and used to resolve the overlapped oxidation signals of dihydroxy benzene isomers. The m/n values obtained at polysorbate/CPE was approximately equal to 1, signifying the transfer of same number of protons and electrons. Moreover, the analytical applicability of the modified electrode for the determination of catechol (CC) and hydroquinone (HQ) in tap water samples gave an acceptable recovery result. Overall, the application of DFT to understand the molecular level interaction of modifiers for sensing applications laid a new foundation for fabricating electrochemical sensors.

Simultaneous electrochemical sensing of dihydroxy benzene isomers at cost-effective allura red polymeric film modified glassy carbon electrode

Background

A simple and simultaneous electrochemical sensing platform was fabricated by electropolymerization of allura red on glassy carbon electrode (GCE) for the interference-free detection of dihydroxy benzene isomers.

Methods

The modified working electrode was characterized by electrochemical and field emission scanning electron microscopy methods. The modified electrode showed excellent electrocatalytic activity for the electrooxidation of catechol (CC) and hydroquinone (HQ) at physiological pH of 7.4 by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques.

Results

The effective split in the overlapped oxidation signal of CC and HQ was achieved in a binary mixture with peak to peak separation of 0.102 V and 0.103 V by CV and DPV techniques. The electrode kinetics was found to be adsorption-controlled. The oxidation potential directly depends on the pH of the buffer solution, and it witnessed the transfer of equal number of protons and electrons in the redox phenomenon.

Conclusions

The limit of detection (LOD) for CC and HQ was calculated to be 0.126 μM and 0.132 μM in the linear range of 0 to 80.0 μM and 0 to 110.0 μM, respectively, by ultra-sensitive DPV technique. The practical applicability of the proposed sensor was evaluated for tap water sample analysis, and good recovery rates were observed.

Graphical abstract

Electrocatalytic interaction of ALR/GCE with dihydroxy benzene isomers.