LC-QTOF-MS method for the analysis of residual pharmaceuticals in wastewater: application to a comparative multiresidue trace analysis between spring and winter water
A sensitive, wide-scope, and trace determination of nine residual pharmaceuticals in wastewater using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF MS) has been developed and validated. After solid-phase extraction with Cleanert PEP cartridges, sample extracts were analyzed by LC-QTOF MS for the simultaneous determination of levofloxacin, tetracycline, ketoprofen, meloxicam, lovastatin and fenofibrate in positive ion mode and chloramphenicol, diclofenac, and ibuprofen in negative ion mode. The separation and determination were performed on a C18 reversed-phase column (4.6 mm × 200 mm, 5 μm) under isocratic conditions. The pH value of the extracts, the type of SPE columns, and the MS conditions were optimized to increase the sample throughput and sensitivity. Quantitation was performed using external quantitation with standard solution mixtures. Under optimal conditions, the mean recovery for all the analytes from the water samples was more than 75.5%.