FAST AND COMPREHENSIVE ANALYSIS OF MAJOR USE ANTIBIOTICS BY UHPLC-HIGH RESOLUTION & HIGH MASS ACCURACY HYBRID LINEAR ION- TRAP- ORBITRAP MASS SPECTROMETRY

Antibiotics constitute one of the most important emerging classes of environmental pollutants. This is due to their diverse use: in veterinary medicine to treat bacterial disease and protect the health of livestock as well as in human medicine to ensure human health safety. They are a prominent group of emerging contaminants frequently found in wastewater effluents and wastewater-impacted aquatic environments. However, the ubiquitous presence of antibiotic residues can create antibiotic-resistant bacteria that are harmful for the aquatic environment along with the consideration to be one of the most serious global threats to human health in the upcoming decades [1, 2]. In this study, antibiotics of multiple classes (sulphonamides, quinolones, penicillins, macrolides, tetracyclines,pyrimidines) were selected to be accurately detected with modern chromatographic systems based on hybrid mass analyzers. For that purpose 13 antibiotics of major use were separated and detected with ultra-high performance liquid chromatography (UHPLC) high-resolution LTQ/Orbitrap mass spectrometry. The recent trend is focused toward the use of powerful high resolution MS detectors like Orbitrap which has become the technique of choice because of its high selectivity and sensitivity. The separation of the target analytes was achieved with a Fortis PFP Hypersil Gold (1.9μm, 50mm x 2.0 mm) analytical column, using a gradient elution system consisting of water (A) and methanol (B) both containing 0.1% formic acid at 400 μL/min flow rate. The target antibiotics were detected as [M+H]+ adduct ions under positive ion mode. Mass accuracy of measured ions was calculated below 3 ppm at 50 ppb, in all cases. The variables involved in the chromatographic process were optimized in instrument auto tune sections. The selected conditions proved to be excellent within 8 min elution with the instrument limits of quantification down to low ppb level for the majority of the analytes. Detector linearity was proved to be excellent in all cases. The excellent analytical characteristics achieved, showed that the proposed analytical protocol is a promising trend that could be fully exploited in the routine monitoring of these antibiotics in several environmental substrates.