Optimization of a Solid-Phase Extraction Method for the Determination of 12 Aminoglycosides in Water Samples Using LC–ESI–MS/MS

A new and simple method has been developed for determination and quantification of 12 aminoglycosides in environmental water samples. The method is based on solid-phase extraction (SPE) followed by liquid chromatography coupled with tandem mass spectrometry (LC–ESI–MS/MS) for analysis. After optimization of LC–ESI–MS/MS conditions, two SPE cartridges, reversed-phase C18 with pentafluoropropionic acid (PFPA) and polymeric mixed mode cation exchange cartridges, have been tested to determine aminoglycoside residues in water. Parameters affecting the extraction efficiency for the two cartridges such as eluent type, percolation volume and percentage of ion pair PFPA were optimized. Extraction on C18 cartridges with PFPA reagent showed a better result in terms of recovery (65–115 %) and relative standard deviation (0.5–15 %) relative to strong cation exchange. This method was validated and their limits of quantification were in the range 5–50 ng L−1. The method was applied to evaluate the occurrence of these compounds in influent and effluent wastewater treatment plant and hospital water samples in Lebanon. Gentamycin was found in hospital wastewater samples at a concentration of 30 ng L−1.