Bienzyme photoelectrochemical biosensor for the sensitive determination of phosphatidylcholine in vegetable oil

Abstract

A bienzyme photoelectrochemical (PEC) biosensor was explored for the sensitive determination of phosphatidylcholine (PC) in vegetable oil based on phospholipase D (PLD) and choline oxidase (ChOx) immobilized on an indium tin oxide (ITO) electrode. The bienzyme electrode is based on the modification with SnO2 nanoparticles (NPs) (SnO2 NPs) and polythionine (PTh). SnO2 NPs were obtained by using a hydrothermal method. Electropolymerization was performed to load the PTh layer on the ITO/SnO2 NPs electrode surface. PLD and ChOx were immobilized on the surface of modified ITO electrode using embedding and cross-linking methods. The prepared ITO/SnO2 NPs/PTh/ChOx/PLD electrode was finally applied as bienzyme PEC biosensor for PC detection. Under optimized conditions, a good linear relationship was obtained in the range of 0.01 mmol/L to 5 mmol/L with a detection limit of 0.002 mmol/L (S/N = 3). The proposed PEC biosensor exhibited remarkable reproducibility, selectivity, and stability. The prepared bienzyme biosensor was used to detect PC in soybean oil by acceptable recoveries. The results were consistent with those of liquid chromatography, confirming the suitability of this PEC sensing strategy for the rapid and sensitive determination of PC in vegetable oil.