Zinc oxide nanoparticles (ZnO NPs) and p-aminobenzenesulfonic acid (p-ABSA) were used to fabricate a modified electrode, as a highly sensitive and selective voltammetric sensor, for the determination of tartrazine. A fast and easy method for the fabrication of poly p-ABSA (Pp-ABSA)/ZnO NPs-carbon paste electrode (Pp-ABSA/ZnO NPs-CPE) by cyclic voltammetry was used. By combining the benefits of Pp-ABSA, ZnO NPs, and CPE, the resulted modified electrode exhibited outstanding electrocatalytic activity in terms of tartrazine oxidation by giving much higher peak currents than those obtained for the unmodified CPE and also other constructed electrodes. The effects of various experimental parameters on the voltammetric response of tartrazine were investigated. At the optimum conditions, the sensor has a linear response in the concentration range of 0349-5.44 μM, a good detection sensitivity (2.2034 μA/μM), and a detection limit of 80 nM of tartrazine. The proposed electrode was used for the determination of tartrazine in soft drinks with satisfactory results.

In the present study, wholly of electrochemical methodology was used to acquire an inexpensive and stable graphene oxide/cobalt oxide nanocomposite on a pencil graphite electrode (PGE). At first, the graphene oxide (GO) nanosheets were directly synthesized at pencil graphite electrode as a carbon source via a potentiostatic method in sulfuric acid solution. Then, cobalt oxide nanoparticles (CoO x NPs) was loaded by cyclic voltammetry on the GO-coated PGE. The morphology of unmodified PGE, GO/PGE and CoO x NP/GO/PGE were characterized by scanning electron microscopy (SEM). The catalytic properties of the quickly designed sensor were used to appraise the electrochemical behavior of insulin. The electroactivity of insulin was significantly enhanced on the CoO x NPs/GO nanocomposite compared with unmodified electrode. A linear dynamic range between 0.46 to 100 nmol dm -3 were obtained with a detection limit of 0.12 nmol dm -3 and a superior detection sensitivity 0.687 μA/nmol dm -3 . Also, the sensor response was not damaged by the presence of common biological intruders such as ascorbic acid, uric acid, citric acid, and glucose. Eventually, three pharmaceutical insulin samples from three different brands (Regular, Isophane, and Lansolin) were selected and analyzed. The recovery percentage suggests that the proposed sensor could be utilized in routine analysis of pharmaceutical preparations.

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The origin of MAMP and its side effects have been reported. The optical and electrochemical sensors for sensing MAMP have been reviewed. The advantages and drawbacks of the applied modifiers and interfaces have been described. The undeniable role of nanotechnology in the expansion of the MAMP sensors has been described. Some offers for commercializing of MAMP sensors for the rutin analysis with low cost have been proposed.

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