Very sensitive electrochemical sensor for moniliformin detection in maize samples

• An electrochemical sensor was developed to determine moniliformin in maize samples.
• A self-assembled monolayer modified gold electrode was used as working electrode.
• Cyclic voltammetry was the electrochemical technique used.
• The calibration curve was linear in the concentration range from 0.12 to 12 ppb.
• Results of the electroanalytical method were in good agreement with those of HPLC.

A highly sensitive electrochemical sensor based on self-assembled monolayers (SAMs) of cysteamine on gold electrodes (Au-CA) in pH 4 citrate buffer solutions was developed to quantify the moniliformin (MON) mycotoxin by cyclic voltammetry in contaminated maize samples. Parameters of SAMs modified gold electrodes such as concentration of thiol, modification time and MON accumulation time were adjusted to obtain the best performance of the sensor. The calibration curve was linear in the MON concentration range from 1 × 10−9 to 1 × 10−7 mol L−1. A limit of detection of 8.3 × 10−10 mol L−1 (0.1 ppb) was obtained. The standard addition method was used to minimize matrix effects. The concentration of MON determined with the electrochemical sensor was in very good agreement with results found by HPLC UV–vis. The sensor showed a good analytical performance with a relative standard deviation (RDS%) of about 3%.

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