On‐chip purification of tetracycline from food matrices

Antibiotics are widespread both to treat human and animal diseases and to improve growth in food animals. However, their overuse in food-producing animals has led to critical issues for human health, such as the direct toxicity and the development of antibiotic-resistant bacterial strains. Therefore, the identification of traces of antibiotic in food before entering the market has became extremely important and brought out the need for novel bioanalytical methods and protocols. To meet this need, here, a microfluidic system was set up for the purification of tetracycline (TC) from raw milk, honey, and eggs. The system is based on the use of magnetic beads exposing copper ions, which are loaded in a microfluidic chamber and actuated by a ready-made device. Tetracycline is captured by copper ions present on the microbeads, purified from the unwanted raw material present in the initial sample and recovered by a suitable elution solution. Different elution solutions were tested and results were evaluated by X-ray photoelectron spectroscopy (XPS) and visible spectrometry. The microfluidic system was successfully employed for the purification of TC from raw milk, honey, and eggs after an initial dilution in buffer. The overall protocol was, therefore, demonstrated to efficiently purify tetracycline, laying the bases for a future implementation of in-field on-chip tests.