Nickel contamination analysis at cost-effective silver printed paper-based electrodes based on carbon black dimethylglyoxime ink as electrode modifier

Electrochemical detection of metal cations at paper-based sensors has been suggested as an attractive alternative to current spectroscopic and chromatographic detection techniques due to the ease of fabrication, disposable nature, and low cost. Herein, a novel carbon black (CB), dimethylglyoxime (DMG) ink is designed as an electrode modifier in conjunction with 3-electrode inkjet-printed paper substrates for use in the adsorptive stripping voltammetric electroanalysis of nickel cations in water samples. Thedeveloped method provides a novel, low-cost, rapid, and portable adsorptive stripping detection approach towards metal analysis in the absence of the commonly used toxic metallic films. The study demonstrated a novel approach to nickel detection at paper-based sensors and builds on previous work in the field of paper-based metal analysis by limiting the use of toxic metal films

Complexation-based detection of nickel(ii) at a graphene-chelate probe in the presence of cobalt and zinc by adsorptive stripping voltammetry

The adsorptive stripping voltammetric detection of nickel and cobalt in water samples at metal film electrodes has been extensively studied. In this work, a novel, environmentally friendly, metal-free electrochemical probe was constructed for the ultra-trace determination of Ni2+ in water samples by Adsorptive Cathodic Stripping Voltammetry (AdCSV). The electrochemical platform is based on the adsorptive accumulation of Ni2+ ions directly onto a glassy carbon electrode (GCE) modified with dimethylglyoxime (DMG) as chelating agent and a Nafion-graphene (NGr) nanocomposite to enhance electrode sensitivity. The nafion-graphene dimethylglyoxime modified glassy carbon electrode (NGr-DMG-GCE) shows superior detection capabilities as a result of the improved surface-area-to-volume ratio and enhanced electron transfer kinetics following the incorporation of single layer graphene, while limiting the toxic effects of the sensor by removal of the more common mercury, bismuth and lead films

Nickel contamination analysis at cost-effective silver printed paper-based electrodes based on carbon black dimethyl-glyoxime ink as electrode modifier

Electrochemical detection of metal cations at paper-based sensors has been suggested as an attractive alternative to current spectroscopic and chromatographic detection techniques due to the ease of fabrication, disposable nature, and low cost. Herein, a novel carbon black (CB), dimethylglyoxime (DMG) ink is designed as an electrode modifier in conjunction with 3-electrode inkjet-printed paper substrates for use in the adsorptive stripping voltammetric electroanalysis of nickel cations in water samples. Thedeveloped method provides a novel, low-cost, rapid, and portable adsorptive stripping detection approach towards metal analysis in the absence of the commonly used toxic metallic films. The study demonstrated a novel approach to nickel detection at paper-based sensors and builds on previous work in the field of paper-based metal analysis by limiting the use of toxic metal films. The device sensitivity is improved by increasing the active surface area, electron transfer kinetics, and catalytic effects associated with non-conductive dimethylglyoxime films through CB nanoparticles for the first time and confirmed by electroanalysis. The first use of the CB-DMG ink allows for the selective preconcentration of analyte at the electrode surface without the use of toxic Mercury or Bismuth metallic films. Compared to similarly reported paper-based sensors, improved limits of detection (48 μg L-1), selectivity, and intermetallic interferences were achieved. The method was applied to the detection of nickel in water samples well below World Health Organization (WHO) standards

Determination of paracetamol on electrochemically reduced graphene oxide–antimony nanocomposite modified pencil graphite electrode using adsorptive stripping differential pulse voltammetry

A simple, highly sensitive, accurate, and low-cost electrochemical sensor was developed for the determination of over-the-counter painkiller, paracetamol (PC). The enhanced sensing capabilities of the developed sensor were fabricated by the single-step modification of disposable pencil graphite electrodes (PGEs) with the simultaneous electrochemical reduction in graphene oxide and antimony (II) salts. For this purpose, an electrochemically reduced graphene oxide–antimony nanoparticle (ERGO-SbNP) nanocomposite material was prepared by trapping metallic nanoparticles between individual graphene sheets in the modification of PGEs

Electrochemically reduced graphene oxide pencil-graphite in situ plated bismuth-film electrode for the determination of trace metals by anodic stripping voltammetry

An electrochemical platform was developed based on a pencil-graphite electrode (PGE) modified with electrochemically reduced graphene oxide (ERGO) sheets and in conjunction with an in situ plated bismuth-film (ERGO-PG-BiE). The ERGO-PG-BiE was used as a sensing platform for determining Zn2+, Cd2+ and Pb2+ by square wave anodic stripping voltammetry (SWASV). ERGO sheets were deposited on to pencil-graphite electrodes by cyclic voltammetric reduction from a graphene oxide (GO) solution. The GO, with flake thicknesses varying between 1.78 to 2.10 nm (2 sheets) was characterized using FT-IR, HR-SEM, HR-TEM, AFM, XRD and Raman spectroscopy. Parameters influencing the electroanalytical response of the ERGO-PG-BiE such as, bismuth-film concentration, deposition potential, deposition time and rotation speed were investigated and optimized. The ERGO-PG-BiE gave well-defined, reproducible peaks with detection limits of 0.19 μg L-1, 0.09 μg L-1 and 0.12 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively, at a deposition time of 120 seconds. For real sample analysis, the enhanced voltammetric sensor proved to be suitable for the detection and quantitation of heavy metals below the US EPA prescribed drinking water standards of 5 mg L-1, 5 μg L-1 and 15 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively

Metallo-Graphene Nanocomposite Electrocatalytic Platform for the Determination of Toxic Metal Ions

A Nafion-Graphene (Nafion-G) nanocomposite solution in combination with an in situ plated mercury film electrode was used as a highly sensitive electrochemical platform for the determination of Zn2+, Cd2+, Pb2+ and Cu2+ in 0.1 M acetate buffer (pH 4.6) by square-wave anodic stripping voltammetry (SWASV). Various operational parameters such as deposition potential, deposition time and electrode rotation speed were optimized. The Nafion-G nanocomposite sensing platform exhibited improved sensitivity for metal ion detection, in addition to well defined, reproducible and sharp stripping signals. The linear calibration curves ranged from 1 μg L−1 to 7 μg L−1 for individual analysis. The detection limits (3σ blank/slope) obtained were 0.07 μg L−1 for Pb2+, Zn2+ and Cu2+ and 0.08 μg L−1 for Cd2+ at a deposition time of 120 s. For practical applications recovery studies was done by spiking test samples with known concentrations and comparing the results with inductively coupled plasma mass spectrometry (ICP-MS) analyses. This was followed by real sample analysis

Few-layer binder free graphene modified mercury film electrode for trace metal analysis by square wave anodic stripping voltammetry

A binding agent free graphene modified glassy carbon electrode in combination with an in situ plated mercury film electrode (Gr-GC-HgFE) was used as a highly sensitive electrochemical platform for the determination of Zn2+, Cd2+ and Pb2+ in 0.1 M acetate buffer (pH 4.6) by square-wave anodic stripping voltammetry (SWASV). Instrumental parameters such as deposition potential, deposition time and electrode rotation speed were optimized. The Gr-GC-HgFE sensing platform exhibited improved sensitivity for metal ion detection, in addition to well defined, reproducible and sharp stripping signals. Two linear calibration curves ranging from 0 –10 μg L−1 and 0 – 60 μg L−1 were identified yielding detection limits of 0.08 μg L−1, 0.05 μg L−1 and 0.14 μg L−1 for Zn2+, Cd2+ and Pb2+, respectively, for simultaneous analysis and 0.04 μg L−1, 0.11 μg L−1 and 0.14 μg L−1 for Zn2+, Cd2+ and Pb2+, respectively, for individual analysis when using a deposition time of 120 s. For practical applications recovery studies using tap water samples spiked with target metal ions gave recoveries within 10% of the spiked amount. Much better recoveries were obtained for the individual analysis in comparison with simultaneous analysis.Web of Scienc

Polyester Sulphonic Acid Interstitial Nanocomposite Platform for Peroxide Biosensor

A novel enzyme immobilization platform was prepared on a platinum disk working electrode by polymerizing aniline inside the interstitial pores of polyester sulphonic acid sodium salt (PESA). Scanning electron microscopy study showed the formation of homogeneous sulphonated polyaniline (PANI) nanotubes (∼90 nm) and thermogravimetric analysis (TGA) confirmed that the nanotubes were stable up to 230 °C. The PANI:PESA nanocomposite showed a quasi-reversible redox behaviour in phosphate buffer saline. Horseradish peroxidase (HRP) was immobilized on to this modified electrode for hydrogen peroxide detection. The biosensor gave a sensitivity of 1.33 μA (μM)-1 and a detection limit of 0.185 μM for H2O2. Stability experiments showed that the biosensor retained more than 64% of its initial sensitivity over four days of storage at 4 °C

Graphene-AuNP enhanced inkjet-printed silver nanoparticle paper electrodes for the detection of nickel(II)-dimethylglyoxime [Ni(dmgH2)] complexes by adsorptive cathodic stripping voltammetry (AdCSV)

Please read abstract in the article.https://analyticalsciencejournals.onlinelibrary.wiley.com/journal/152141092021-10-14hj2021Electrical, Electronic and Computer Engineerin

Electrochemical immunosensor based on polythionine/gold nanoparticles for the determination of Aflatoxin B1

An aflatoxin B1 (AFB1) electrochemical immunosensor was developed by the immobilisation of aflatoxin B1-bovine serum albumin (AFB1-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB1-BSA conjugate was covered with horseradish peroxidase (HRP), in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB1 immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV) peak separation (ΔEp) value of 62 mV. The experimental procedure for the detection of AFB1 involved the setting up of a competition between free AFB1 and the immobilised AFB1-BSA conjugate for the binding sites of free anti-aflatoxin B1 (anti-AFB1) antibody. The immunosensor’s differential pulse voltammetry (DPV) responses (peak currents) decreased as the concentration of free AFB1 increased within a dynamic linear range (DLR) of 0.6 - 2.4 ng/mL AFB1 and a limit of detection (LOD) of 0.07 ng/mL AFB1. This immunosensing procedure eliminates the need for enzyme-labeled secondary antibodies normally used in conventional ELISA–based immunosensors