Analytical & Bioanalytical Electrochemistry
Volume:13 Issue: 3, Dec 2021

Paracetamol (PCM) drug used in the treatment of pain, fever and headache, and it is considered safely for human use subjects. It has been found that the overdose and the chronic use of PCM produces toxic effects of environmental and immediate allergic hypersensitivity. Therefore, it is essential to develop sufficiently sensitive and simple sensors for precise determination of PCM. Chemically modified carbon-based electrodes have been widely used in this approach. This review is focused on the use of various chemically modified carbon-based electrodes such as glassy carbon, carbon paste, carbon screen-printed, graphene paste, and boron doped diamond electrodes in the electrochemical detection of PCM. Finally, we have briefly summarized the recent chemically modified carbon-based electrodes for the determination of PCM using articles encompassing 2018 until June 2020 and the efficiency of sensors are compared in terms of linear range, limits of detection and other proprieties can affect PCM detection as pH, medium, potential oxidation.

A novel screen printed graphite ion-selective electrode (SPE) was prepared and characterized for determination of linagliptin (LNG) in pure form and in pharmaceutical formulation. The electrode is based on LNG-tetraphenyl borate (LNG-TPB) as ion exchanger and tricresyl phosphate (TCP) as a plasticizer. Several parameters such as the type of solvent mediator, amount of the ion-exchanger and working pH range were studied for optimal potentiometric response. Under optimal experimental conditions, the sensor exhibited a Nernstian slope of 60.10±1.02 mV/decade (n=3) over the concentration range from 1.00×10-5 to 1.00×10-2 M (r =0.9999) with LOD of 4.50×10-6 M. The electrode can be used safely over a wide pH range from 4.0 to 8.0. The electrode showed a high selectivity for LNG against common interfering substances. Fast potentiometric response was obtained within 5 seconds and remained stable for at least 60 S. The electrode was applied to the analysis of LNG in pure form and in pharmaceutical dosage form with high accuracy (98.00-102.00%) and precision (%RSD ≤2%). Our electrode has the advantages of being inexpensive, simple, sensitive, portable and disposable.

The aim of this work is the study of the inhibition corrosion of copper in hydrochloric acid solution 2M using essential oil of ammodaucus leucotrichus Coss. & Dur. noted (AEO). Its protective ability is evaluated by weight loss measurements, electrochemical impedance spectroscopy (EIS) and polarization curves, at different concentrations of the oil (0-3000 ppm) and by varying the temperature of the solution (298-328K). The polarization curves highlight the cathodic character of this eco-friendly inhibitor. However, the corrosion rate was reduced when the concentration of AEO is increased and achieves about 70% after 6h immersion in corrosive media containing 3000 ppm of AEO. This important protection ability is relied to the formation of a protective film over the metal, which its adsorption is governed by the Langmuir isotherm model. The negative values of the free standard adsorption energy ΔGads confirm the spontaneity of the reaction. Interestingly, scanning electron microscopy (SEM) analysis underlines a remarkable enhancement on the surface of copper exposed to the corrosive media, in presence of AEO and hence, its efficiency as an ecofriendly inhibitor for copper surface.

A new differential pulse voltammetric method was developed for determination of the non-steroidal anti-inflammatory drug; acemetacin. Various experimental parameters were studied, namely; electrode type, pH of the used buffer and scan rate on the reduction and oxidation peaks of acemetacin. The drug responded only to glassy carbon electrode among the studied working electrodes with higher peak current and sensitivity in the favor of the reduction side. The results also revealed that acemetacin best assayed through measuring its reduction peak current when prepared in Britton Robinson buffer solution at pH 8 when scanned at rate of 16 mV/s. The proposed method presented a bimodal calibration curve where each segment showed strong linearity. The linearity ranges were 1 - 100 µM for the lower segment and 0.1 - 3 mM for the higher one with detection limit of 0.1 µM. The proposed method was successfully applied for determination of acemetacin in its pharmaceutical dosage form.

In this work, we investigated the applicability of the clay-modified carbon paste electrode (CPE-clay) in the detection of paracetamol (PAR), using two electrochemical methods differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the range between 20 and 400 mV in a Britton Robinson buffer solution (pH 7). The voltammetric technical behavior of PAR is studied where a sensitive anodic and cathodic peak has been appeared at about 0.4 V and 0.2 V (vs. Ag/AgCl/3 M KCl) successively. These peaks were recorded from the reversible redox of PAR at the CPE-clay surface. The proposed technical (DPV, CV) exhibits remarkably an electro-catalytic success for PAR redox. The current response of the catalytic peaks obtained by DPV depended linearly on the concentration of PAR in the range between 1.0 × 10-6 and 1.0 × 10-3 mol L-1 with a detection limit of 5.27 × 10-9 mol L-1. Subsequently, the relative standard deviation (RSD) at 1.0 × 10-4 mol L-1 PAR concentration was 3.8% for nine replicates. The proposed electrode has been successfully used for PAR detection in the human blood sample.

The research on the preparation and characterization of Pb2+ Ion Selective Electrode (ISE) using dithizone (DTZ) as ion carrier has been done. Membrane of ISE was made with the optimum composition with ratio of DTZ : PVC : DOP was 6 : 3 : 1. The membrane was doped using 1M Pb2+ solution within 7 days, and characterized using FT-IR to determine the shift of wave number from the spectrum of the group from membrane before and after doped. The results of characterization of FT-IR spectra of membrane after doped, shows that there is a shift of wave number from absorption spectra of secondary amine (N-H) group and absorption spectra of thiol (S-H) group didn’t appear. The result of characterization of Pb2+ ISE shows that ISE worked well with range concentration of 1×10-4 - 1×10-1 M, with Nernst slope was 29.5 mV/decade and the limit of detection was 1.5×10-4 M. The electrode worked optimally at pH 5, the response time was 9-48 seconds and can be used within 6 weeks. The presence of interfere ions, such as Ag+, Zn2+, Cu2+, Cd2+, Cl- and SO42- didn’t affect to the determination of Pb2+ ions in the samples.

A chemically modified carbon paste electrode (CPE) based on SnO2/α-Fe2O3 hierarchical nanorods (SFOHNRs) were constructed as a novel simple electrochemical sensor for a sensitive simultaneous determination of dopamine (DA) and tramadol (TRA). To investigate electrochemical behaviors of DA and TRA several techniques such as differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods were used. SFOHNRs were fabricated via three step process. In order to characterize SFOHNRs several techniques such as field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) technique and energy dispersive X-ray spectroscopy (EDX) were used. Application of SFOHNRs as the modifier of the CPE (SFOHNRs/CPE) showed high oxidation peak currents for determination of DA and TRA due to its catalytic effect and its high surface area. Using DPV technique, the sensor showed linear ranges of 0.1-70 µM and 0.5-65 µM and low detection limits of 40 nM and 65 nM toward DA and TRA, respectively. The fabricated sensor exposed excellent sensitivity, simplicity and high selectivity toward simultaneous determination of DA and TRA. The analytical performance of the sensor has been evaluated for analysis of DA and TRA in human blood serum and urine with satisfactory results.

Abstract- For the first time, this study used agarose gel as a membrane in electro membrane extraction (AG-EME) without using any organic solvent to preconcentrate and clean up nilotinib in biological samples, following: its spectrofluorometric determination. Optimal conditions were: agarose concentration (w/v) 3.0%, acetic acid concentration in membrane (v/v) 0.2%, applied electric voltage 50V, pH of the donor phase (pHd) 4, pH of the acceptor phase (pHa) 3, and extraction time of 30 min. Limits of detection (LOD) and quantification (LOQ) were 15 and 50 ng mL˗1, and the analytical curve was linear at the range of 50–5000 ng mL˗1. The proposed validation method was compared with the other electro-membrane extraction techniques. Our proposed method is fast; it uses little sample and possesses a short extraction time. The developed procedure could be utilized successfully to determine the total amount of nilotinib, an anticancer drug, as a routine analysis in the biological samples.

Since the selectivity of an ion selective sensor is directly related to the stability constants of ion–ionophore complexes, we predicted the complexation stability (K) of cerium ions with different ionophores by the quantitative structure–property relationship model. Genetic algorithm (GA) feature selection approach was selected to choose the proper molecular descriptors which were then subjected to multiple linear regression (MLR) for prediction of the log K. The predictive ability of the built genetic algorithm-multiple linear regression (GA-MLR) model was evaluated using Leave-one-out cross-validation, Leave-group-out cross-validation, Y-randomization, and test set compounds. Statistical parameters of the model (R2train=0.852, Q2LOO= 0.813, and Q2LGO=0.777) indicated the ability of the GA-MLR model to predict the response of ionophores in cerium-selective sensors based on complex stability constants. Also, the applicability domain of the model was analyzed by the Williams plot. Based on this study, some key features are identifiable to appraise the selectivity of cerium sensors that can be used to design new selectophores.

Magnesium imprinted polymeric (Mg-IP) nanoparticles were prepared by precipitation polymerization method in acetonitrile. Itaconic acid (ITA) and ethylene glycol dimethacrylate were employed as functional monomer/complexing agent and cross-linker, respectively. Fast fourier-infrared spectroscopy was employed to investigate the interaction of ITA with Mg2+ ion. The obtained polymeric material was utilized as ionophore in order to fabricate the Mg2+-selective PVC-membrane electrode. The Mg-IP nanoparticles were covalently modified with alkyl chains, capping the surface carboxylic acid groups of the IPs and making them much hydrophobic. This strategy caused remarkably improvement in the electrode selectivity and durability. The optimized electrode showed response time of about 25 s and exhibited no memory effect. A dynamic linear range of 5×10-7 to 1×10-1 mol L-1, Nernstian slope of 29.5±(0.4) mV decade-1 and detection limit of 2.3×10-7 mol L-1 were attained for the electrode. The efficiency of the electrode was tested by the determination of Mg2+ amount in different bottled mineral water and drinking water samples.