Electropolymerization of thiophene on gold nanoparticle modified electrode in aqueous media

Spectro-Electrochemical Properties of A New Non-Enzymatic Modified Working Electrode Used for Histamine Assessment in the Diagnosis of Food Poisoning

We successfully prepared a non-enzymatic sensor based on a graphene-thiophene composite for histamine detection. The self-assembling properties of the thiophene onto Au support and the high electrical conductivity of graphene encouraged the choice of this type of composite. The composite was deposited via electrochemical polymerization onto the Au layer of a screen-printed microelectrode. The electropolymerization and electrochemical detection of histamine were both achieved by cyclic voltammetry. Two types of electrolytes were used for the electrochemical detection: (a) phosphate buffer solution (PBS), which showed low-intensity redox peaks for histamine; and (b) trichloroacetic acid (TCA) 0.01 M, which showed improved results over PBS and did not damage the microelectrode. For the concentration range of 100-200 mg/kg, the sensor shows a linear regression pattern for the oxidation peak fitted on the equation Ipa = 123.412 + 0.49933 ×x, with R2 = 0.94178. The lowest limit of detection was calculated to be 13.8 mg/kg and the limit of quantification was calculated at 46 mg/kg. These results are important since by monitoring the amount of histamine in a food product, early onset of spoilage can be easily detected, thus reducing foodborne poisoning and food waste (by recycling products that are still edible).

Direct and one-step synthesis of polythiophene/gold nanoparticles thin films through liquid/liquid interfacial polymerization

This work demonstrates a simple and one-step synthesis of polythiophene/gold nanoparticles (PT/Au) nanocomposite thin films, through a liquid-liquid (L/L) interfacial polymerization route. Starting from an aqueous solution of tetrachloroauric acid (acting both as metallic gold source and oxidizing agent to start the oxidative polymerization of thiophene), and a solution of thiophene in n-hexane, a biphasic L/L system was originated. In the following, the interface acted as a meeting-point for the reactants, and the polymerization reaction took place, leading to self-assembled PT/Au film between the two immiscible liquids. These films were easily deposited over different substrates (glass, silicon, plastics) and characterized through different techniques. The influence of both the reactants ratio and the reaction time on the structure and morphology of the films were evaluated. The films obtained with a shorter reaction time exhibited spherical gold nanoparticles (around 3 nm diameter) homogeneously dispersed into a polymeric matrix. The increase of both the reaction time and the thiophene/gold precursor ratio led to agglomerated and anisotropic gold structures wrapped by a thin layer of polythiophene. Overall, PT/Au films are transparent, homogeneous, stable, flexible and presented reversible electrochromic properties, which make them suitable for application in different systems and devices, as demonstrated here for electrochromic application.

An effect of the substituent position and metal type on the electropolymerization properties of chalcone substituted metallophthalocyanines

Cobalt(ii) and manganese(iii) phthalocyanines bearing peripherally and non-peripherally tetra substituted {(2E)-3-[4-(dimethylamino)phenyl]prop-2-enoyl}phenoxy groups were synthesized by cyclotetramerization of the phthalonitrile derivatives and their electrochemical properties were examined using CV and SWV techniques for the first time.

Development of a simple bioelectrode for the electrochemical detection of hydrogen peroxide using Pichia pastoris catalase immobilized on gold nanoparticle nanotubes and polythiophene hybrid

We have developed an electrochemical H₂O₂ biosensor using AuNPNTs PTh and CAT_pp.