Efficient capture of fluoroquinolones in urine and milk samples with multi-monolith fibers solid phase microextraction based on hybrid metal–organic framework/monolith material

Abstract

To capture fluoroquinolones (FQs) from complex samples efficiently, a new hybrid metal–organic framework (MOF)@monolith material (HMM) was fabricated and employed as the extraction medium of multi-monolith fibers solid phase microextraction (MMF-SPME). Porous monolithic fibers based on allyltrimethylammonium chloride-co-ethylene glycol dimethacrylate/divinylbenzene polymer were fabricated firstly. After that, the strategy of layer-by-layer self-assembly was employed to prepare zeolitic imidazolate frameworks within the pores and the surface of the monolith. Various characterization results well evidenced that the introduction of MOF not only enhanced the surface area of adsorbent, but also introduced new active sites. The prepared HMM/MMF-SPME presented satisfactory capture performance towards studied FQs by multiple interactions. Enrichment factors of FQs in human urine and milk samples were in the ranges of 99–128 and 85–121, respectively. Under the most beneficial fabrication and extraction parameters, HMM/MMF-SPME was combined with high-performance liquid chromatography to quantify trace FQs in urine and milk samples. High sensitivity (limits of detection were 0.0072–0.031 μg/L for urine sample and 0.016–0.057 μg/kg for milk sample) and good precision (RSDs below 10%) were obtained. In the analysis of FQs in actual samples, the recovery at different spiked contents varied from 77.4% to 120%, with good reproducibility. Accuracy and reliability of established approach were well verified with confirmation experiments. Satisfactory results evidence that the developed HMM/MMF-SPME can be a prominent technique for the capture of trace FQs in complex samples.