Application of aptamer‐conjugated graphene oxide for specific enrichment of microcystin‐LR in Achatina fulica prior to matrix‐assisted laser desorption ionization mass spectrometry

Abstract Microcystin‐LR (MC‐LR), as a hepatotoxin, can cause liver swelling, hepatitis, and even liver cancer. In this study, MC‐LR aptamer (Apt‐3) modified graphene oxide (GO) was designed to enrich MC‐LR in white jade snail ( Achatina fulica ) and pond water, followed by matrix‐assisted laser desorption ionization mass spectrometry (MALDI‐MS) analysis. Results indicated that the Apt‐3/PEG/GO nanocomposites were highly specific to MC‐LR, and the detection limit of MALDI‐MS was 0.50 ng/mL. Moreover, the MC‐LR can be released from nanocomposites at 75°C, thus, the reuse of Apt‐3/PEG/GO is realized. Real sample analysis indicated that the Apt‐3/PEG/GO nanocomposites coupled with MALDI‐MS were efficient in detecting trace amounts of MC‐LR in real samples. With the merits of being low cost, reusable, and easy to besynthesized, this Apt‐3/PEG/GO MALDI‐MS is expected to be comprehensively applied by anchoring suitable aptamers for different targets.