An Aptamer Affinity Column for Extraction of Four Aminoglycoside Antibiotics from Milk

This article introduces the aptamer affinity column (AAC) with nucleic acid aptamer as an affinity ligand for the extraction of four aminoglycoside antibiotics (AGs). The AAC was prepared by loading the aptamer functionalized Sepharose into an extraction column, which was conjugated by covalent binding between NHS-activated Sepharose and amino-modified aptamers with a coupling time of 2 h. After the sample solution flowed through the AAC, the AGs were retained because of the affinity between the AGs and aptamer, then AGs were eluted and analyzed by UPLC-MS/MS. Under the optimized conditions, the maximum adsorption of AGs on the AAC could reach 8.0 μg. Moreover, the proposed AAC could be reused more than 20 times. The resultant AAC that conjugated with the aptamer was successfully applied in the enrichment and purification of four AGs in a milk sample and good recovery results in the range of 83.3–98.8% were obtained (with RSD in the range of 0.6–5.8%). The proposed AAC for recognition of multi-target AGs exhibited good enrichment and purification effects, showing great application potential for targets with their related aptamers.