Voltammetric Determination of Various Food Azo Dyes Using Different Modified Carbon Paste Electrodes

The food industries are developing very fast by improving the taste, odor, appearance of various food products. To do so, they are adding a variety of preservatives, sweeteners, and coloring agents and attracting a huge community of people. Dyes or coloring agents play an important role in enriching food's appearance, quality, and taste. Most used food coloring agents are synthetic azo dyes. They are cheaper than natural dyes, therefore, they are used in huge amounts very frequently. Most of the azo dyes like Amaranth, Tartrazine, Allura Red AC, and Metanil Yellow can cause serious health issues for all the living system, and therefore the use of them in food should be controlled, or the optimum level of these dyes in food and beverages should be measured. Many methods like thin layer chromatography, mass spectroscopy, spectrophotometry, capillary electrophoresis, cyclic voltammetry, high-performance liquid chromatography are used to detect azo dyes in the food. But cyclic voltammetry method is one of the simple, robust, highly selective, accurate, high speed, economical, and highly sensitive methods to determine the presence of azo dyes in foods. The main subject of this review article is the detection of several azo dyes utilizing modified carbon paste electrodes and cyclic voltammetry.

Influence of Nitrogen-Doped Carbon Dot and Silver Nanoparticle Modified Carbon Paste Electrodes on the Potentiometric Determination of Tobramycin Sulfate: A Comparative Study

Two inexpensive and simple methods for synthesis of carbon nanodots were applied and compared to each other, namely a hydrothermal and microwave-assisted method. The synthesized carbon nanodots were characterized using transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis), photoluminescence (PL), Fourier transform-infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The synthesized microwave carbon nanodots had smaller particle size and were thus chosen for better electrochemical performance. Therefore, they were used for our modification process. The proposed electrodes performance characteristics were evaluated according to the IUPAC guidelines, showing linear response in the concentration range 10−6–10−2, 10−7–10−2, and 10−8–10−2 M of tobramycin with a Nernstian slope of 52.60, 58.34, and 57.32 mV/decade for the bare, silver nanoparticle and carbon nanodots modified carbon paste electrodes, respectively. This developed potentiometric method was used for quantification of tobramycin in its co-formulated dosage form and spiked human plasma with good recovery percentages and without interference of the co-formulated drug loteprednol etabonate and excipients.

Design and construction of a carbon paste electrode modified with molecularly imprinted polymer-grafted nanocomposites for the determination of thyroxin in biological samples

In this study, a novel nano-molecularly imprinted polymer was synthesized and used to prepare modified carbon paste electrodes.