Development of an amperometric biosensor based on peroxidases from Brassicas napus for the determination of Ochratoxin a content in peanut samples

Abstract

An amperometric biosensor based on Brassica napus hairy roots peroxidases (BHRP) to determine ochratoxin A (OTA) is proposed by the first time. The enzymatic reaction rate was studied under different experimental conditions and the kinetics parameters were determined. The method employs a dialysis membrane covered, peroxidases entrapped and ferrocene-embedded carbon paste electrode (BHRP-Fc-CP) and is based on the decrease in the amount of H2O2 produced by the action of BHRP is proportional to the concentration of oxidised OTA in solution. BHRP-Fc-CP biosensors showed a very good stability during at least five days. The reproducibility and the repeatability were 7.7% and 5.4%, respectively, showing a good biosensor performance. Comparison between intra and inter assays showed a good accuracy. The calibration curve was linear in the OTA concentration range from 1 x 10-8 to 1.4 x 10-4 mol L-1. The lowest concentration experimentally measured for a signal to noise ratio of 3:1 was 5.7x10-9 mol L-1.