▎ 摘　　要

NOVELTY - A free aptamer marker sensing and ultra-low concentration ochratoxin-A detecting method involves using o-amino thiophenol functionalized graphene oxide and chloroauric acid as initial raw material, sodium citrate as reducing agent, followed by preparing modified gold nanoparticles functionalized graphene oxide. The modified gold nanoparticles functionalized graphene oxide is taken as carrier and loaded with thiol-modified single-stranded DNA3 sequence to obtain single-stranded DNA3 sequence modified gold nanoparticles functionalized graphene oxide, followed by modifying gold electrode surface. USE - Method for sensing free aptamer marker and detecting ultra-low concentration ochratoxin-A. ADVANTAGE - The method enables sensing free aptamer marker and detecting ultra-low concentration ochratoxin-A with high sensitivity in a simple, inexpensive and rapid manner. DETAILED DESCRIPTION - A free aptamer marker sensing and ultra-low concentration ochratoxin-A detecting method involves using o-amino thiophenol functionalized graphene oxide (GO-SH) and chloroauric acid as initial raw material, sodium citrate as reducing agent, followed by preparing modified gold nanoparticles functionalized graphene oxide (Au-S- rGO). The modified gold nanoparticles functionalized graphene oxide is taken as carrier and loaded with thiol-modified single-stranded DNA3 sequence to obtain single-stranded DNA3 sequence modified gold nanoparticles functionalized graphene oxide (DNA3-Au-S- rGO), followed by modifying gold electrode surface by thiol-modified single-stranded DNA1 sequence, pairing single-stranded DNA2 sequence modified aptamer to the electrode surface through complementary base, and sensing interface with different concentrations of OTA reaction, where the single-stranded DNA1 sequence comprises 5'-hs-tgt ccg atg ctc-3', the single-stranded DNA2 sequence comprises 5'-gatcgg gtg tgg gtg gcg (tm) agg gag cat cgg aca-3' and the single-stranded DNA3 sequence comprises 5'-cca cac ccg atc-sh-3'.