Determination of Aflatoxin B1 in Peanut Oil by an Enzyme-Inhibited Gold Nanocolorimetric Sensor
An efficient and convenient method for determining aflatoxin B1(AFB1)was established.With ace-tylcholine thio(ATCh)as the substrate,the effect of AFB1 on the bioactivity of acetylcholinesterase(AChE)was studied.The results indicated that thiocholine(TCh)could be adsorbed on the surface of gold nanopar-ticles(AuNPs)in the form of Au-S covalent form,which led to the polymerization of AuNPs and the gradual color change from burgundy to blue-gray in visible light.Meanwhile,the local surface plasmon resonance ab-sorption peaks at the wavelength of 522 nm decreased in turn.When AFB1 was present in a sample,the bio-logical activity of AChE was inhibited,which reduced hydrolysis of ATCh to TCh.Based on the determination of the change of UV-vis absorption peaks at 522 nm before and after the inhibition,a rapid,simple,and sensi-tive colorimetric method for the visualization of AFB1 was constructed,which realized and the detection of trace AFB1 in samples.The optimal reaction conditions were as follows:pH7.4,AChE concentration of 2 500 mU/mL,substrate concentration of 5µmol/L,and reaction time of 60 min.The linear range of AFB1 was 0.1-20 ng/mL,and the limit of detection was 0.03 ng/mL.The spiked recovery of the actual peanut oil samples ranged from 93.4%to 104.9%.The results indicated that the established method had high sensitivity and accu-racy for the determination of AFB1 in food.
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