The invention relates to a preparation method of a photoelectrochemical sensor for detecting
patulin. The
patulin is a
mycotoxin produced by a plurality of
penicillium,
aspergillus and ascomycetes, and is easy to dissolve in water. The wide
pollution of the strain to agricultural products forms a significant
health risk to consumers. Therefore, it is necessary to develop a method for rapidly detecting
patulin. According to the research, a novel dual-mode
aptamer sensor is constructed, and ultra-sensitive detection of patulin is realized by integrating photoelectrochemical and colorimetric sensing technologies; the sensor adopts
zinc phthalocyanine sensitized
sulfur indium zinc as a high-performance photoactive material, and shows enhanced light absorption capability and
charge separation efficiency; the
lanthanum-doped
nickel cobaltate nano-
enzyme material is used as a
bifunctional signal probe, so that the light current of a photosensitive material can be effectively quenched, and the
lanthanum-doped
nickel cobaltate nano-
enzyme material can be used as a nano-
enzyme to catalyze colorimetric reaction; through a cyclic amplification strategy assisted by
exonuclease III, the sensor can detect patulin with high sensitivity, and the
absorbance of an o-phenylenediamine oxidation product is weakened along with the increase of the concentration of patulin and the increase of the light current intensity; the
aptamer sensor has an ultra-wide
linear range of 0.00001-100 ng / mL, the detection limits respectively reach 0.0027 pg / mL (
photoelectrochemistry) and 0.03 ng / mL (colorimetric method), and meanwhile, the
aptamer sensor shows excellent selectivity, stability and reproducibility; a satisfactory
recovery rate is achieved in actual apple and hawthorn juice sample detection, and it is proved that the method has important application value in the field of
food safety monitoring.