Very sensitive electrochemical sensor for moniliformin detectionin maize samples

Abstract

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%.