Development of an electrochemical sensor modified with gold nanoparticles for detecting fumonisin B1 in packaged foods

Abstract

Fumonisin B1 (FB1) is naturally present in the environment and can easily contaminate packaged foods during processing, storage and transportation, thus posing a threat to human health. We have developed an enzyme-free FB1 detector for the detection of packaged foods, which provides rapid and sensitive detection of FB1 in food. Gold nanoparticles (AuNPs; 5-10 nm) were uniformly dispersed on screen-printed electrodes, which acted as an excellent catalytic oxidizer. The surface structure of the modified electrode was characterized using scanning electron microscope and X-ray photoelectron spectroscopy. Differential pulse voltammetry demonstrated a good linear electrochemical response towards FB1 at concentrations ranging from 1 ng L^-1 to 1 mg L^-1 with a detection limit of 0.08 ng L^-1. We employed the AuNPs-SPE sensor to detect FB1-spiked packaged meat products achieving recovery rates ranging from 89.7% to 113.3%.

Fig. 1. SEM images of bare SPE (×50 k; A) and of AuNPs-SPE (×50 k; B). The AFM 2D and 3D surface morphology of bare SPE(C and E) and of AuNPs-SPE(D and F). XPS images of the AuNPs-SPE sensor (G), Au 4f (H); AuNPs-SPE (E), bare SPE (F), AuNPs-SPE (G).

Fig. 2. Cyclic voltammograms (CVs) of 0.1 M PBS of different pH values (4, 5, 6, 7, 7.4, 8). Inset: the influence of pH on the current.

Fig. 3. (A) CVs of FB1 (0.1 mg L⁻¹) in 0.1 M PBS (pH = 7.4) of the bare SPE and AuNPs-SPE. (B) DPVs of FB1 (0.1 mg L⁻¹) in 0.1 M PBS (pH = 7.4) of the bare SPE and AuNPs-SPE. The blue line coincides with the green line. (C) The CV of 10 mL PBS in 0.1 M FB1 on the AuNPs-SPE.

Scheme 1. The electrooxidation mechanism of FB1.

Fig. 4. (A) DPVs of FB1 with different concentrations of the AuNPs-SPE. FB1 concentrations ranged from 1 ng L⁻¹ to 1 mg L⁻¹. The concentration of the next one is 10 times that of the previous one. (B) Linear relationship between current intensity and the concentration of FB1.

Fig. 5. Detection of multiple compounds by the AuNPs-SPE. The concentration of FB1 was 1 μg mL⁻¹.

Fig. 6. (A) Bar plots of the cathodic peak current of four different AuNPs-SPES. (B) Thirty CV results of the AuNPs-SPE in PBS.