Evaluating on-line solid-phase extraction coupled to liquid chromatography–ion trap mass spectrometry for reliable quantification and confirmation of several classes of antibiotics in urban wastewaters

This study provides an evaluation of on-line solid-phase extraction (SPE) and liquid chromatography (LC) in combination with ion trap (IT) mass spectrometry for the simultaneous routine analysis of 12 antibiotics belonging to multiple classes together with carbamazepine and propranolol in sewage treatment effluents. The on-line SPE step warranted high sensitivity and high sample throughput while IT mass detection provided high selectivity for confirmation of positive samples. A single extraction procedure resulted in recoveries ranging from 40% to 120%. Limits of detection were in the 1–46 ng/L range, which constitutes an improvement of a factor of 10 with respect to the off-line SPE procedure.