Solid-phase microextraction of antibiotics from fish muscle by using MIL-101(Cr)NH 2 -polyacrylonitrile fiber and their identification by liquid chromatography-tandem mass spectrometry

Antibiotics are a group of antibacterial drugs used in the treatment and prevention of bacterial diseases in humans, veterinary animals, and farmed fish. Inappropriate and excessive use of antibiotic therapy leads to antibiotic fragment in the water bodies thus affect the aquatic organisms. In this study, an amino group modified high surface area metal-organic framework (MOF) MIL-101(Cr)-NH was used to prepare solid-phase microextraction (SPME) fiber to detect four different classes (total 6 ABs) of antibiotics for the first time from living tilapia fish (Oreochromis mossambicus) by coupling SPME with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The extraction efficiencies of the custom-made fiber were superior as compared with the commercial C18, polydimethylsiloxane (PDMS), PDMS/divinylbenzene (DVB) and polyacrylate fibers. The custom-made fiber also exhibited excellent reproducibility with the low intra-fiber relative standard deviations (RSDs 1.5%-8.3%) and inter-fiber RSDs (7.3%-14.5%), which made it ideal for in vivo extraction in fish muscle. The as-prepared MIL-101(Cr)-NH fiber was then used to determine antibiotics in the dorsal-epaxial muscle of living fish. Comparing to the traditional solid-liquid extraction (SLE) method, the SPME method showed reduced invasiveness and higher sensitivity than the SLE method. In general, this study explored a convenient, cost-effective and highly sensitive SPME method based on amino modified MOF for in vivo antibiotic detection in fish muscle.