scholarly journals Voltammetric Immunosensor to Track a Major Peanut Allergen (Ara h 1) in Food Products Employing Quantum Dot Labels

Biosensors ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 426
Author(s):  
Maria Freitas ◽  
Henri P. A. Nouws ◽  
Cristina Delerue-Matos
Keyword(s):  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Electrochemical Immunosensor ◽  
Allergic Reactions ◽  
Peanut Allergen ◽  
Ara H 1 ◽  
Hands On ◽  
Sandwich Type ◽  
Assay Time

Tracking unreported allergens in commercial foods can avoid acute allergic reactions. A 2-step electrochemical immunosensor was developed for the analysis of the peanut allergen Ara h 1 in a 1-h assay (<15 min hands-on time). Bare screen-printed carbon electrodes (SPCE) were used as transducers and monoclonal capture and detection antibodies were applied in a sandwich-type immunoassay. The short assay time was achieved by previously combining the target analyte and the detection antibody. Core/shell CdSe@ZnS Quantum Dots were used as electroactive label for the detection of the immunological interaction by differential pulse anodic stripping voltammetry. A linear range between 25 and 1000 ng·mL−1 (LOD = 3.5 ng·mL−1), an adequate precision of the method (Vx0 ≈ 6%), and a sensitivity of 23.0 nA·mL·ng−1·cm−2 were achieved. The immunosensor was able to detect Ara h 1 in a spiked allergen-free product down to 0.05% (m/m) of peanut. Commercial organic farming cookies and cereal and protein bars were tested to track and quantify Ara h 1. The results were validated by comparison with an ELISA kit.

scholarly journals Sandwich Electrochemical Immunosensor for Early Detection of Tuberculosis Based on Graphene/Polyaniline-Modified Screen-Printed Gold Electrode

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3926 ◽  
Author(s):  
Umi Mohd Azmi ◽  
Nor Yusof ◽  
Norzila Kusnin ◽  
Jaafar Abdullah ◽  
Siti Suraiya ◽  
...  
Keyword(s):  
Gold Electrode ◽  
Differential Pulse ◽  
Sample Volume ◽  
Electrochemical Immunosensor ◽  
X Ray ◽  
Sandwich Type ◽  
Pulse Voltammetry ◽  
Culture Filtrate Protein ◽  
Cast Technique ◽  
Screen Printed

A rapid and sensitive sandwich electrochemical immunosensor was developed based on the fabrication of the graphene/polyaniline (GP/PANI) nanocomposite onto screen-printed gold electrode (SPGE) for detection of tuberculosis biomarker 10-kDa culture filtrate protein (CFP10). The prepared GP/PANI nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The chemical bonding and morphology of GP/PANI-modified SPGE were studied by Raman spectroscopy and FESEM coupled with energy dispersive X-ray spectroscopy, respectively. From both studies, it clearly showed that GP/PANI was successfully coated onto SPGE through drop cast technique. Cyclic voltammetry was used to study the electrochemical properties of the modified electrode. The effective surface area for GP/PANI-modified SPGE was enhanced about five times compared with bare SPGE. Differential pulse voltammetry was used to detect the CFP10 antigen. The GP/PANI-modified SPGE that was fortified with sandwich type immunosensor exhibited a wide linear range (20–100 ng/mL) with a low detection limit of 15 ng/mL. This proposed electrochemical immunosensor is sensitive, low sample volume, rapid and disposable, which is suitable for tuberculosis detection in real samples.

scholarly journals The effect of tamoxifen on the electrochemical behavior of Bi+3/Bi on the glassy carbon electrode and its determination via differential pulse anodic stripping voltammetry

2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Mehdi Jalali ◽  
Zeinab Deris Falahieh ◽  
Mohammad Alimoradi ◽  
Jalal Albadi ◽  
Ali Niazi
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Peak Height ◽  
Carbon Electrode

The electrochemical behavior of Bi+3 ions on the surface of a glassy carbon electrode, in acidic media and in the presence of tamoxifen, was investigated. Cyclic voltammetry, chronoamperometry, differential pulse voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy were used to find the probable mechanism contributing to the reduction of the peak height of bismuth oxidation with an increase in the concentration of tamoxifen. The obtained results show a slight interaction between the bismuth species and tamoxifen which co-deposit on the surface of glassy carbon electrode. Therefore, the reduction in the peak height of bismuth oxidation as a function of tamoxifen concentration was used to develop a new differential pulse anodic striping voltammetry method for determination of trace amount of tamoxifen. The effects of experimental parameters on the in situ DPASV of Bi+3 ions in the presence of tamoxifen shown the optimal conditions as: 2 mol L-1 H2SO4 (1% v v-1 MeOH), a deposition potential of -0.5 V, a deposition time of 60 s, and a glassy carbon electrode rotation rate of 300 rpm. The calibration curve was plotted in the range of 0.5 to 6 µg mL-1 and the limits of detection and quantitation were calculated to be 3.1 × 10-5 µg mL-1 and 1.0 × 10-4 µg mL-1, respectively. The mean, RSD, and relative bias for 0.5 µg mL-1 (n=5) were found to be 0.49 µg mL-1, 0.3%, and 2%, respectively. Finally, the proposed method was successfully used for the determination of tamoxifen in serum and pharmaceutical samples.

scholarly journals Thallium Associated with Manganese Ore Tailings in a Deactivated Mine in the Western Region of Bahia, Brazil

2021 ◽  
Author(s):  
Jorge Luís Santos ◽  
Giuliana Bueno ◽  
Eder Flores ◽  
Oldair Leite ◽  
Clayton Janoni ◽  
...  
Keyword(s):  
Anodic Stripping Voltammetry ◽  
Extraction Procedure ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Rare Metal ◽  
Western Region ◽  
Natural Occurrence ◽  
Flame Atomic Absorption ◽  
The Western Region ◽  
Environmental Agencies

Thallium (Tl) is a rare metal with toxic effects notably harmful to human health and the environment. In this article, the natural occurrence of Tl was evaluated in a deactivated manganese mine located in the Western region of Bahia, Brazil. The extraction procedure with aqua regia was used to dissolve the soil, sediment, and tailings samples. The Tl content was determined by differential pulse anodic stripping voltammetry (DPASV) and manganese (Mn) and iron (Fe) by flame atomic absorption spectroscopy (FAAS). The Tl levels ranged from 0.64 to 473 mg kg‑1, triggering an alert since most of the samples (soil and sediment) analyzed presented Tl concentrations above 1.0 mg kg-1, recognized as the maximum limit recommended by environmental agencies in North America and Europe.

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