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

Abstract

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 I_pa = 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).

Keywords: Raman spectroscopy; cyclic voltammetry; electropolymerization; food poisoning; histamine; non-enzymatic sensor.

Figure 1

Variation of the peak intensities and charges of the polymerization process vs. the No. of cycles: (a) anodic peak intensity vs. No. of cycles; (b) charge variation for the anodic peak vs. No. of cycles; (c) first cathodic peak (−98 mV) intensity vs. No. of cycles; (d) charge variation for the first cathodic peak (−98 mV) vs. No. of cycles; (e) second cathodic peak (424 mV) intensity vs. No. of cycles; and (f) charge variation for the second cathodic peak (424 mV) vs. No. of cycles.

Figure 2

Raman spectra of the thiophene and of the electropolymerized film deposited onto the Au working electrode.

Figure 3

(a) Cyclic voltammetry of different concentrations of histamine in 0.01M TCA. (b) Electrochemical analysis of a solution containing histamine and two interferents.

Figure 4

Variation of the concentration of histamine in TCA with (a) peak intensities and (b) charge.