Application of UHPLC-MS/MS method to study occurrence and fate of sulfonamide antibiotics and their transformation products in surface water in highly urbanized areas

Sulfonamide antibiotics (SAs) are used on a large scale in human and veterinary medicine. The main goal of this study was to develop a method for the detection of selected SAs (sulfamethoxazole, sulfadiazine, sulfamethazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethiazole, and sulfisoxazole) in aqueous samples (targeted analysis), and then conduct a non-targeted analysis to determine the transformation products to elucidate their degradation pathways. These analyses were performed using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The procedure was used to detect selected antibiotics in water samples collected throughout a highly urbanized area. Among the studied compounds, sulfamethoxazole (max. 78.88 ng L-1) and sulfapyridine (max. 38.88 ng L-1) were the most common pollutants identified in surface waters. Trace amounts of sulfadiazine (below LOQ = 0.40 ng L-1) were also detected. Next, the samples were screened to detect the transformation products. Several sulfadiazine and sulfamethoxazole transformation products were detected and confirmed in the environmental samples.

Automated summary

A method was developed to detect sulfonamide antibiotics in water samples and non-targeted analysis was conducted to determine their transformation products in this study. Sulfamethoxazole and sulfapyridine were identified as the most common pollutants in surface waters, with trace amounts of sulfadiazine also detected. Several transformation products of sulfadiazine and sulfamethoxazole were confirmed in environmental samples during the screening process.