LC-QqLIT MS analysis of nine sulfonamides and one of their acetylated metabolites in the Llobregat River basin. Quantitative determination and qualitative evaluation by IDA experiments

Robust instrumental analytical chemistry and the subsequent development of improved analytical methodologies and extraction procedures have enabled the detection at environmental levels of new emerging contaminants, for example pharmaceuticals. The objective of this study was to explore the potential of liquid chromatography–tandem quadrupole-linear ion trap (LC–QqLIT MS) for quantitative determination of nine sulfonamides (SAs) and one acetylated metabolite in surface water from the Llobregat River and one of its main tributaries, the Anoia River, in Catalonia (Spain). A total of 21 samples were taken in three sampling campaigns. Recoveries ranging from 26% to 123% were calculated for the SAs studied, and method limits of detection (MLODs) achieved were in the range 0.05–0.2 ng L⁻¹. Through the different campaigns, concentrations ranged from 0.74 ng L⁻¹ (sulfamethizole) to 2,482 ng L⁻¹ (sulfamethazine) in the Llobregat River, and from 0.27 ng L⁻¹ (sulfamethizole) to 168 ng L⁻¹ (sulfamethoxazole) in the Anoia River. Sulfamethoxazole and sulfapyridine were the two SAs most frequently detected (80% and 71% respectively). N ⁴-acetylsulfamethazine was detected in both rivers, but with different frequencies (4% of the samples from the Anoia River and 43% of those from the Llobregat River). Information-dependent acquisition (IDA) experiments were also developed in order to obtain enhanced product-ion spectra in surface water samples.