Fabrication Of Glassy Carbon Electrode Research Articles

Novel Electrochemical Sensor for Rifampicin based on Ionic Liquid Functionalised TiO2 Nanoparticles

Aim::The main strategy of this study is to develop a novel ionic liquid functionalised metal nanocomposite based electrochemical sensor with potential applications for the sensitive electrochemical detection of rifampicin.Background::Tuberculosis (TB) is a widespread disease that is caused by the gram-positive Mycobacterium tuberculosis (MTB). In addition, for several decades TB has become a constant threat to human health, however due to the accessibility of broad-spectrum antibiotics (rifampicin, pyrazinamide, isoniazid, and ethambutol), which are active against the bacterium, the social and economic burden for sufferers from the illness remains to be huge. Specially, in countries, like India and sub Saharan Africa, it is one of the common diseases affecting members from all age groups. So, this work is aimed at developing a novel electrochemical sensor for the determination of rifampicin (RIF) in pharmaceutical samples.Objective::To synthesis and characterization of the novel liquid functionalised metal nanocomposite. Fabrication of glassy carbon electrode with potent electrode modifiers whose applicability as electro catalysis agents towards rifampicin is investigated.Method::In this work, a nanocomposite based on trihexyltetradecylphosphonium-bis-(2,4,4-trimethylpentyl)-phosphinate ([P14, 6, 6, 6] [(C8H17)2 PO2)]) ionic liquid functionalised titanium oxide nanoparticles (TiO2NPs) and multiwalled carbon nanotubes (MWCNTs) were used in the modification of a highly sensitive electrochemical sensor for quantification of rifampicin in pharmaceutical formulations. The modified glassy carbon electrode (GCE) were characterised by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).Results::The electrochemical behaviour of RIF was studied on the modified electrode by the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. At pH 6.0 in phosphate buffer solution (PBS), the anodic peak current value of RIF obtained with the fabricated electrode is 7 times greater than with the bare GCE electrode. The anodic peak current value and concentration of RIF showed a good linear relationship in the range of 0.015–2.8 μM, with the limit of detection (LOD) of 0.0218 μM and limit of quantification (LOQ) 0.3120 μM respectively.Conclusion::Under the optimal conditions, the IL-f-TiO2NPs-MWCNTs-GCE provided a relatively lower detection limit and wider linear range compared to other previous procedures. The proposed electrochemical sensor had potent catalytic activity for RIF oxidation and provided important quantitatively reproducible analytical performance. Finally, this modified electrode was successfully applied to the determination of RIF in real pharmaceutical samples.

Development of a L‐cysteine Sensor Based on Thallium Oxide Coupled Multi‐walled Carbon Nanotube Nanocomposites with Electrochemical Approach

Here, nanocomposites of thallium oxide doped multi-walled carbon nanotube (Tl2 O MWCNT NCs) were prepared by utilizing a wet-chemical method (WCM) in an alkaline phase at low temperature. Different optical procedures (FTIR: Fourier Transform Infra-Red Spectroscopy, XRD: Powder X-ray diffraction, FESEM: Field-Emission Scanning Electron Microscopy, XEDS: X-ray Electron Dispersive Spectroscopy, TEM: Tunneling Electron Microscopy, and XPS: X-ray photoelectron spectroscopy) were used to fully characterize (optical, structural, crystalline, morphological, and elemental etc.) of the prepared Tl2 O MWCNT NCs. Modification of the thin-layer with NCs onto glassy carbon electrode (GCE) is prepared and applied for the selective and sensitive enzyme-free detection of L-cysteine by an electrochemical approach. Using a reliable current-voltage approach, analytical sensing indexes such as sensitivity, LDR, LOD, LOQ, durability, and interference were assessed by fabricated sensor probe (GCE/Tl2 O MWCNT NCs/CPM) in selective detection of L-cysteine at room temperature, whereas nafion was used as conducting polymer matrix (CPM) during the fabrication of GCE with NCs. L-cysteine calibration plot was found to be linear over an extensive range of concentration. The calibration curve was used to calculate the sensing parameters such as sensitivity (316.46 pAμM-1 cm-2 ), LOD down to (∼18.90±1.89 pM), and LOQ (63.0 pM) of the prepared sensor. The use of a simple WCM to validate the Tl2 O.MWCNT NCs is a good approach for developing a NCs-based sensor for enzyme-free biomolecule identification and detection in the biomedical and health care fields in a broad scale. This proposed sensor (GCE/Tl2 O MWCNT NCs/CPM) is used to detect selective L-cysteine in real biological samples such as human, mouse, and rabbit serum and found acceptable and satisfactory results.

Electrochemically Deposited Porous Graphene−Polypyrrole−Polyphenol Oxidase for Dopamine Biosensor

AbstractWe report a method for the fabrication of glassy carbon electrode modified porous graphene‐polypyrrole‐polyphenol oxidase (GCE−PG−PPy−PPO) modified electrode for the determination dopamine. The optimization of pH, concentration and detection limit of dopamine was employed by amperomatric technique. The detection limit of dopamine was found to be in a linear range of 2×10−8 to 4.6×10−5 M and lower limit detection is 4×10−9 M. Michealis – Menten constant (Km) and the activation energy were calculated as 31.32 μM and 37.4−Kj mol−1, respectively. The developed biosensor was used to quantify the dopamine in human urine sample.

Dual-recognition molecularly imprinted aptasensor based on gold nanoparticles decorated carboxylated carbon nanotubes for highly selective and sensitive determination of histamine in different matrices

In this study, an electrochemical aptamer based sensor (aptasensor) was proposed for specific recognition of histamine (HIS). The electrochemical aptasensor based on fabrication of glassy carbon electrode (GCE) with molecular imprinted polymer (MIP) and DNA aptamers on gold nanoparticles (AuNPs) and carboxylated carbon nanotubes (cCNTs) (MIP-apta/AuNPs/cCNTs/GCE). The aptasensor exhibits high selectivity towards HIS detection as it has two recognition elements which are MIP cavities and aptamer interaction. Upon exposure of MIP-apt/AuNPs/cCNTs/GCE to HIS, the current of redox probe was decreased that depends on the template (HIS) concentration. The effects of aptamer concentration, incubation time, pH and AuNPs electro-deposition time were optimized. Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques were used to analyze HIS in complicated matrices. Favorable performance of MIP-apt/AuNPs/cCNTs/GCE was achieved with linearity ranges of 0.46–35 nmol L−1 and 0.35–35 nmol L−1 with limits of detection (LODs, S/N = 3) of 0.15 nmol L−1 and 0.11 nmol L−1 using DPV and EIS, respectively. The fabricated aptasensor displayed high selectivity, desirable reproducibility and stability. The MIP-apt/AuNPs/cCNTs/GCE was used to detect HIS in human plasma and canned tuna samples with good recoveries % and RSDs %.

Development of tribenzamide functionalized electrochemical sensor for femtomolar level sensing of multiple inorganic water pollutants

A novel tribenzamides derivative N-{4-[2-(1,3-Benzoxazolyl)]phenyl}-3,5-N,N′-bis(4-hexyloxybenzoyl)benzamide (BOC6), containing three amide groups, was successfully synthesized and characterized through multiple spectroscopy techniques. The ultrasensitive electrochemical platform was developed by fabrication of glassy carbon electrode (GCE) with synthesized multifunctional tribenzamide appended BOC6 for the removal of water pollutants. The performance of the engineered sensor was studied by its electrochemical characterization with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave anodic stripping voltammetry (SWASV). The modifier played a facilitating role between the GCE surface and the target metal ions by bringing analytes closer to transducer surface resulting in appearance of intense electrochemical signals. Under pre-defined optimized conditions of SWASV, the BOC6 modified electrode was able to attain distinct oxidative current signals of thallium, arsenic, and mercuric ions simultaneously in one voltammogram scan. The sharp electrochemical signal and peak potential shift of thallium (Tl), arsenic (As) and mercury (Hg) oxidation at −0.79 V, −0.06 V and 0.22 V respectively, versus reference electrode Ag/AgCl evidence the electrocatalytic role of BOC6/GCE as compared to bare GCE at −0.68 V, −0.01 V and 0.3 V, respectively. Moreover, it was found to sense femtomolar concentration of aforementioned toxic ions, much lower than the world health organization (WHO) and environmental protection agency (EPA) guidelines for drinking water [1]. The limit of detections (LODs) obtained on for Tl(I), As(III), and Hg(II) detection were 2.19 fM, 1.97 fM, and 2.52 fM, respectively. Conclusively, the designed electrode was portable, cost effective, resistant to the interference species, highly stable and gives repeatable and reproducible voltammograms of analytes via strong interactions with target ions even in real water samples.

CeO2/g-C3N4 nanocomposite: A perspective for electrochemical sensing of anti-depressant drug

Herein, a binary composite electrode comprising CeO2 nanoparticles and g-C3N4 sheets were investigated for electrochemical determination of an anti-depressant drug Agomelatine (AG). The nanocomposite was utilized for fabrication of glassy carbon electrode (GCE) via simple casting method and characterized for morphology and composition using various advanced characterization tools which indicated successful loading of CeO2 nanoparticles on g-C3N4 sheets. The modified sensor was employed for electrochemical study of AG using cyclic voltammetry (CV) and square wave voltammetry (SWV). A significant enhancement was observed in anodic peak current at CeO2/g-C3N4/GCE, as compared to bare electrode, due to reduction in charge transfer resistance and augmentation in electron transfer process. Electroactive surface area of modified sensor was found to be 0.204 cm2 which was almost 8 times higher than bare electrode. A diffusion-limited process involving equal number of protons and electrons controlled the electrochemical oxidation of AG with the sensor. Under optimized conditions, the modified sensor displayed linear response over a concentration range of 1-20 ng/ml, limit of detection (LOD) 0.96 ng/ml and limit of quantification (LOQ) 2.92 ng/ml. The developed method was successfully applied to determine AG in commercial tablets with satisfactory recovery results along with good reproducibility, selectivity and stability.

Novel synthesis and characterization of Ag@TiO2 core shell nanostructure for non-enzymatic glucose sensor

Ag@TiO2 core-shell nano composite (ATCSNC) were synthesized by using Ocimum tenuiflorum leaves extract through a simple one-step hydrothermal route for Non-enzymatic glucose sensing material. The prepared NCs were characterized and found high crystallinity, red shift absorbance, interface-bonding parameters, rough surface and network like microstructure through XRD, Uv–vis, FTIR, SEM, and TEM. The prepared ATCSNC have been used for fabrication of glassy carbon electrode (GCE) and the same was applied to test its electro catalytic activity of glucose in 0.1 M NaOH. The promising results were recorded for ATCSNC/GCE with a high sensitivity (1968.72 μAm M−1 cm−2), wide linear range (1 μM–8.1 mM), good response time (3 s), and excellent low detection limit (0.19 μM, S/N = 3). Furthermore, the designed sensor exhibits admirable stability and reproducibility, as well as attractive achievability for real sample analysis. As such, the proposed ATCSNC could be highly beneficial in the development of sustainable and eco-friendly glucose sensing devices.

Amperometric sensing of hydrogen peroxide using glassy carbon electrode modified with copper nanoparticles

In this paper, fabrication of glassy carbon electrode (GCE) modified with nano copper particles is discussed. The modified electrode has been tested for the non-enzymatic electrochemical detection of hydrogen peroxide (H2O2). The copper nanoparticles (Cu NPs) were prepared employing a simple chemical reduction method. The presence of Cu NPs was confirmed through UV–visible (UV–vis) absorption spectroscopy and X-ray diffraction (XRD) analysis. The size and morphology of the particles were investigated using transmission electron microscopy (TEM). The electrochemical properties of the fabricated sensor were studied via cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The electrochemical sensor displayed excellent performance features towards H2O2 detection exhibiting wide linear range, low detection limit, swift response time, good reproducibility and stability.