Aptamer‐modified magnetic metal‐organic framework MIL‐101 for highly efficient and selective enrichment of ochratoxin A

Abstract

A facile and efficient strategy is developed to modify aptamers on the surface of the magnetic metal‐organic framework MIL‐101 for the rapid magnetic solid‐phase extraction of ochratoxin A. To the best of our knowledge, this is the first attempt to create a robust aptamer‐modified magnetic MIL‐101 with covalent bonding for the magnetic separation and enrichment of ochratoxin A. The saturated adsorption of ochratoxin A by aptamer‐modified magnetic MIL‐101 was 7.9 times greater than that by magnetic metal‐organic framework MIL‐101 due to the former's high selective recognition as well as good stability. It could be used for extraction more than 12 times with no significant changes in the extraction efficiency. An aptamer‐modified magnetic MIL‐101‐based method of magnetic solid‐phase extraction combined with ultra high performance liquid chromatography with tandem mass spectrometry was developed for the determination of trace ochratoxin A with limit of detection of 0.067 ng/L. Ochratoxin A of 4.53–13.7 ng/kg was determined in corn and peanut samples. The recoveries were in the range 82.8–108% with a relative standard deviation (n = 5) of 4.5–6.5%. These results show that aptamer‐modified magnetic MIL‐101 exhibits selective and effective enrichment performance and have excellent potential for the analysis of ultra‐trace targets from complex matrices.

Preparation of aptamer‐bound polyamine affinity monolithic column via a facile triazine‐bridged strategy and application to on‐column specific discrimination of ochratoxin A

“…A significant improvement of reaction efficiency was achieved with a high coverage density of aptamer up to 1799 pmol/μL. By using the most‐abundant mycotoxins ochratoxin A (OTA) as model analyte, the affinity performance of the resultant monolith was studied and a sensitive detection of OTA was carried out with a level as low as 10 pg/mL, which was better than that of affinity monoliths prepared from amine‐activated matrixes reported previously. It provided a simple protocol for fabricating a high‐performance polyamine affinity monolith for highly specific recognition.…”

Recent Advances in Affinity MOF-Based Sorbents with Sample Preparation Purposes

“…Aptamers are highly comparable to antibodies, although they show several advantages, such as cheap chemical fabrication, superior stability, and high reproducibility. Despite these unique properties, these molecules have been scarcely incorporated in MOF supports for sample treatment purposes due to their relatively short existence time [ 62 , 63 , 64 , 65 , 66 ]. Lin and co-workers [ 62 , 63 ] developed two aptamer-MOF devices for the selective extraction of polychlorinated biphenyls (PCBs) in soil and fish samples followed by GC-MS analysis.…”

“…Additionally, aptamer-functionalized MOF materials have been applied for food safety purposes [ 65 , 66 ]. As an example, Zhang et al [ 65 ] synthesized a magnetic MOF (MIL-101) coupled with an aptamer for the enrichment of ochratoxin A in corn and peanut samples, and the determination was followed by UHPLC-MS-MS. The analytical features of the optimized method were as follows: a satisfactory recovery (82.8–108%), good loading capacity (553 pmol mg −1 ), acceptable reusability of sorbent (at least 12 times), and low LOD (67 pg L −1 ).…”

Aptamer-based and immunosorbents

“…mainly hydrophobic and/or electrostatic interactions favored in aqueous media. The comparison of the retention of the target analyte on the IS/OS with the nongrafted solid-support, named control sorbent (17,21,34,36,37,(40)(41)(42)(44)(45)(46)(47)70,71,(73)(74)(75)(76)84), or grafted with another antibody/oligonucleotide sequence, having no affinity for the target (18,21,25,34,36,37,42,47,48,54,55,70,84), is now often reported to evaluate the contribution of these NSIs. The use of these sorbents in parallel to IS/OS is particularly helpful for optimizing the washing step and then obtaining an optimal selectivity (48,57).…”