Immobilization of anti-aflatoxin B1 antibody by UV polymerization of aniline and aflatoxin B1 detection via electrochemical impedance spectroscopy

Figures & data

Figure 1. EIS spectrums of the immobilization steps of the biosensor [a: Bare gold electrode, b: after UV polymerization. Working conditions: Incubation period for anti-aflatoxin B1 antibody:30 min., stirring rate: 100 r.p.m., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V, bias potential: 0.025 V].

Figure 2. Cyclic voltammograms for the immobilization steps of the biosensor [Thicker line: bare gold electrode; thinner line: after UV polymerization. Working conditions: Incubation period for anti-aflatoxin B1 antibody: 30 min., stirring rate: 100 r.p.m., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V, bias potential: 0.025 V].

Figure 3. The effect of aflatoxin B1 incubation period on the biosensor response [Incubation periods: -●-●-: 30 min. -▲-▲-: 20 min. -■-■-: 10 min. Working conditions: Incubation period for anti-aflatoxin B1 antibody: 30 min., stirring rate: 100 r.p.m., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V, bias potential: 0.025 V].

Figure 4. The effect of stirring rate on the biosensor response and bioactive layer [Stirring rates(r.p.m.): -●-●-: 100, -▲-▲-: 300, -■-■-: 600, -♦-♦-: 900, -Δ-Δ-: to stir for the first 2 min at 300 r.p.m. Working conditions: Incubation period for anti-aflatoxin B1 antibody: 30 min., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V, bias potential: 0.025 V].

Figure 5. The optimization of bias potential applied to the system [Bias potentials tested: -♦-♦-: 10 mV, -■-■-: 25 mV, -▲-▲-: 50 mV, -x-x-: 75 mV, -*-*-: 100 mV, -●-●-: 150 mV, + - + -: 200 mV. Working conditions: Incubation period for anti-aflatoxin B1 antibody: 30 min., stirring rate: 100 r.p.m., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V].

Figure 6. Nyquist plots for increasing concentrations of aflatoxin B1 [Working conditions: Incubation period for anti-aflatoxin B1 antibody: 30 min., stirring rate: 100 r.p.m., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V, bias potential 0.025 V].

Figure 7. Calibration curve for aflatoxin B1 [Working conditions: Incubation period for anti-aflatoxin B1 antibody: 30 min., stirring rate: 100 r.p.m., electrochemical redox prob solution: Fe(CN)₆^{3 − /4 −} , 0.005 M + 0.1 M KCl, frequency range: 0.1–100000 Hz, AC potential: 0.01 V, bias potential 0.025 V].

Table I. The reproducibility of the biosensor based on anti-aflatoxin B1 antibody.

Biosensors	R^2	Linear ranges (ng/mL)
1	0.919	20-Jan
2	0.99	20-Jan
3	0.994	20-Jan
4	0.996	20-Jan
5	0.893	20-Jan

Table II. Aflatoxin B1 detection in peanut sample spiked with aflatoxin B1 by the biosensor.

Aflatoxin B1 (ng/mL)*
Added	Found by the biosensor	% Recovery after extraction	% Relative difference
0.2	0.21	105	5

* The average of six measurements.