Biotic transformation products of sulfonamides in environmental water samples: High-resolution mass spectrometry-based tentative identification by a suspect screening approach.

The presence of pharmaceuticals in the aquatic environment is mainly due to their release from the effluents of the wastewater treatment plants (WWTPs), which are unable to completely remove them and their transformation products (TPs). Sulfonamides (SAs) are a synthetic antibacterial class used for the treatment of both human and animal infections; they have often been reported in surface water, thus contributing to the antibiotic resistance emergency. Monitoring SA TPs should be important as well because they could still exert some pharmaceutical activity; however, many TPs are still unknown since several transformation processes are possible (e. g. human and animal metabolism, WWTP activities, environmental factors etc.). In this work, three of the most used SAs, i.e., sulfamethoxazole (SMX), sulfapyridine (SPY), and sulfadiazine (SDZ), were incubated for 20 days in a batch reactor with activated sludge under controlled conditions. Then, the water sample was extracted and analyzed by ultra-high performance liquid chromatography-high resolution mass spectrometry in the data dependent acquisition (DDA) mode. Starting from the literature data, the possible transformation pathways were studied, and for each SA, a list of TPs was hypothesized and used for the identification. The raw data files were processed with Compound Discoverer, and 44 TPs (18, 13, and 13 TPs for SMX, SPY, and SDZ, respectively), including multiple TPs, were manually validated. To overcome the limitation of the DDA, the identified TPs were used in an inclusion list to analyze WWTP samples by a suspect screening approach. In this way, 4 SMX TPs and 5 SPY TPs were tentatively identified together with their parent compounds. Among these TPs, 5 of 9 were acetylated forms, in agreement with previous literature reporting that acetylation is the predominant SA transformation.

Untargeted analysis of environmental contaminants in surface snow samples of Svalbard Islands by liquid chromatography-high resolution mass spectrometry.

In recent years, there is increasing attention on the contaminants of emerging concern (CECs), which include plasticizers, flame retardants, industrial chemicals, pharmaceuticals, and personal care products, since they have been detected even far away from pollution sources. The polar regions are not exempt from the presence of anthropogenic contaminants, and they are employed as a model for understanding the pollutant fate and impact. During the 2021 spring campaign, sixteen surface snow samples were collected close to the research station of Ny-Ålesund located on the Spitsbergen Island of the Norwegian Svalbard Archipelago. The samples were extracted by solid-phase extraction and analyzed by liquid chromatography-high-resolution tandem mass spectrometry (LC-HRMS/MS) following an untargeted approach. Compound tentative identification was obtained with the aid of the software Compound Discoverer, using both mass spectral database search and manual validation. Among the 114 compounds identified with a high confidence level in the snow samples, >80 have some commercial or industrial use (drugs, plasticizers, fragrances, etc.), therefore they could be of anthropogenic origin. Nonetheless, a clear contamination trend did not appear in the snow samples collected on eight different days during one month. The comparison with aerosol samples collected in the same area did not help identifying the source, either, since only a few compounds were in common, and they were mainly of natural origin. As such, the analysis of aerosol sample did not support possible long-range transport, also considering that compounds were detected mostly in the coarse fraction.