Determination of multi-class pharmaceuticals in wastewater by liquid chromatography-tandem mass spectrometry (LC-MS-MS)

An analytical method for multi-class pharmaceuticals determination in wastewater has been developed and validated. Target compounds were: sulfonamides (sulfadiazine, sulfaguanidine, sulfamethazine, sulfamethoxazole), fluoroquinolones (ciprofloxacin, enrofloxacin, norfloxacin), diaminopyrimidine (trimethoprim), anaesthetic (procaine), anthelmintic (praziquantel and febantel), and macrolide (roxithromycin). The method involves pre-concentration and clean-up by solid-phase extraction (SPE) using Strata-X extraction cartridges at pH 4.0. Target analytes were identified and quantitatively determined by liquid chromatography-tandem mass spectrometry using multiple reaction monitoring (MRM). Recoveries were higher than 50% with relative standard deviation (RSD) below 18.3% for three concentrations. Only for sulfaguanidine was low recovery obtained. Matrix effect was evaluated using matrix-matched standards. The method detection limit (MDL) was between 0.5 and 5 ng L-1 in spiked water samples. The precision of the method, calculated as relative standard deviation, ranged from 0.5 to 2.0% and from 1.4 to 8.3 for intra-day and inter-day analysis, respectively. The described analytical method was used for determination of pharmaceuticals in effluent wastewaters from the pharmaceutical industry.