Development of a bio-electrochemical assay for AFB1 detection in olive oil.
A novel biosensor assay format for aflatoxin based on acetylcholinesterase (AChE) inhibition by aflatoxin B(1) (AFB(1)) is proposed. The AChE was present in solution and an amperometric choline oxidase biosensor was used for monitoring its residual activity. To create the biosensor, the choline oxidase was immobilized by cross-linking onto screen-printed electrodes modified with Prussian Blue (PB) and these were used to detect the H(2)O(2) at low potential (-0.05V versus a screen-printed internal silver pseudoreference electrode). For the development of the AFB(1) assay, several parameters such as AChE and substrate concentration, the methanol effect, and pH were evaluated and optimized. The linear working range was assessed to be 10-60ppb. Concentrations as low as 2ppb, which correspond to the legal limit of AFB(1) in food for humans, were detected after a pre-concentration step. The suitability of the method was evaluated using commercial olive oil samples. A recovery equal to 78+/-9% for 10ppb of AFB(1) in olive oil samples was obtained.
Ben Rejeb
Ines
I
Biocatalysis and Bioprocess Unit, National Institute of Applied Science and Technology (INSAT), B.P. 676, 1080 Tunis Cedex, Tunisia.
Arduini
Fabiana
F
Arvinte
Adina
A
Amine
Aziz
A
Gargouri
Mohamed
M
Micheli
Laura
L
Bala
Camelia
C
Moscone
Danila
D
Palleschi
Giuseppe
G
D000110:Acetylcholinesterase / Q000737:chemistry*; D016604:Aflatoxin B1 / Q000032:analysis*; D000429:Alcohol Oxidoreductases / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D000069463:Olive Oil; D010938:Plant Oils / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004800:Enzymes, Immobilized; D000069463:Olive Oil; D010938:Plant Oils; D016604:Aflatoxin B1; D000429:Alcohol Oxidoreductases; C019888:choline oxidase; D000110:Acetylcholinesterase