Accurate quantification of quinolones in marine sediment by UPLC-MS/MS after ultrasonic extraction and automated SPE...

As a class of the most prevalent broad-spectrum antibiotics, quinolones (QNs) are ubiquitous in various environmental matrices (in particular marine sediment). However, determination of multiple QNs in marine sediment is a challengeable task due to matrix complexity and strong QNs-sediment adsorption. Herein we presented an efficient quantification strategy for accurate measurement of 15 QNs in marine sediment based on ultrasonic extraction with 0.2 M Na₂HPO₄ in 50 v/v % acetonitrile, followed by automated solid-phase clean-up and ultra-performance liquid chromatography-tandem mass spectrometry with isotope dilution calibration. The method demonstrated negligible matrix effect, satisfactory recoveries (85 %-119 %), and low limits of detection (2-15 pg/g). Five QNs were detected in marine sediment from Yueqing Bay and Daiquyang with total concentrations of 5.6-12.1 μg/kg and 0.2-1.0 μg/kg, respectively, where four QNs including norfloxacin (NOR), enrofloxacin, ciprofloxacin, and ofloxacin were found in all samples, and NOR was the predominant compound both in Yueqing Bay and Daiquyang. Overall, the presented method is highly sensitive and reliable for routine quinolone analysis in marine sediment.