A Voltammetric Biosensor Based on Glassy Carbon Electrodes Modified with Single-Walled Carbon Nanotubes/Hemoglobin for Detection of Acrylamide in Water Extracts from Potato Crisps

Abstract

The presence of toxic acrylamide in a wide range of food products such as potato crisps, French fries or bread has been confirmed by Swedish scientists from Stockholm University. The neurotoxicity, possible carcinogenicity of this compound and its metabolites compels us to control them by quantitative and qualitative assays. Acrylamide forms adduct with hemoglobin (Hb) as a result of the reaction the -NH2 group of the Nterminal valine with acrylamide. In this work we present the use of glassy carbon electrodes coated with single-walled carbon nanotubes (SWCNTs) and Hb for voltammetric detection of acrylamide in water solutions. The electrodes presented a very low detection limit (1.0×10^-9 M). The validation made in the matrix obtained by water extraction of potato crisps showed that the electrodes presented are suitable for the direct determination of acrylamide in food samples.

Keywords: Acrylamide; OSWV; SWCNTs; hemoglobin; potato crisps.

Figure 1.

(A) The CV curves for GCE/SWCNT/Hb measured in solution containing NaCl 0.05 M and acetate buffer 0.2 M pH = 5.0 vs scan rates: 0.01, 0.02, 0.03, 0.04, 0.05, 0.075, 0.1, 0.2, 0.3, 0.4, 0.5, 0.75, 1.0, 2.0, 3.0, 5.0, 9.0 V/s. (B) Linear relationship between cathodic and anodic peak current vs. scan rate.

Figure 2.

The OSWV curves for electrodes modified with SWCNT/Hb measured in the presence of various concentrations of acrylamide. The electrolyte composition: 0.05 M NaCl, 0.2 M acetate buffer pH = 5.0. The concentration of analyte was, as follows: (A) 0, (B) 1.0 × 10⁻¹¹, (C) 1.0 ×10⁻¹⁰, (D) 1.0 × 10⁻⁹, (E) 1.0 × 10⁻⁸, (F) 1.0 × 10⁻⁷, (G) 1.0 × 10^-6, (H) 1.0 × 10^-5, (I) 1.0 × 10^-4, (J) 1.0 × 10^-3 M.

Figure 3.

The ratio of OSWV peak current in the presence of different concentration of acrylamide (I_p) to that in the absence of acrylamide (I_p,0) as a function of the acrylamide concentration. The currents were measured at the peak potential in OSWV curves in the solution with no analyte E_p,0. Results obtained for electrodes modified with SWCNT, E_p,0=46 mV, n=4, 2.2<SD<7.7 ( ) and SWCNT/Hb, E_p,0=44 mV, n=3, 0.9<SD<4.4 ( ).

Figure 4.

The response of Hb/SWCNT/GCE electrodes towards acrylamide in the presence of water extract from the potato crisp. The ratio of OSWV peak current in the presence of a given concentration of acrylamide (I_p) to that in absence of analytes (I_p,0) was plotted versus the concentration of acrylamide in water extract from the potato crisp. The currents were measured at the peak potential in OSWV curves in the solution with no analyte (E_p,0 = 38 mV); (n = 3; 3.1 < S.D. < 7.5).