Identification of the specified impurities of silver sulfadiazine using a screening of degradation products in different stress physico-chemical media

Application of UHPLC-MS/MS method to monitor the occurrence of sulfonamides and their transformation products in soil in Silesia, Poland

Sulfonamides circulating in the environment lead to disturbances in food chains and local ecosystems, but most importantly contribute to development of resistance genes, which generate problems with multidrug-resistant bacterial infections treatment. In urban areas, sources of sulfonamide distribution in soils have received comparatively less attention in contrast to rural regions, where animal-derived manure, used as a natural fertilizer, is considered the main source. The aim of this study was to determine eight sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfamethizole, sulfamethoxazole, sulfapyridine, sulfathiazole, and sulfisoxazole) in environmental soil samples collected from urbanized regions in Silesian Voivodeship with increased animal activity. These soils were grouped according to the organic carbon content. It was necessary to develop versatile and efficient extraction and determination method to analyze selected sulfonamides in various soil types. The developed LC-MS/MS method for sulfonamides analyzing was validated. The obtained recoveries exceeded 45% for soil with medium organic carbon content and 88% for sample with a very low organic carbon content (arenaceous quartz). The obtained results show the high impact of organic matter on analytes adsorption in soil, which influences recovery. All eight sulfa drugs were determined in environmental samples in the concentration range 1.5-10.5 ng g-1. The transformation products of the analytes were also identified, and 29 transformation products were detected in 24 out of 27 extracts from soil samples.

Solar-light driven photodegradation of antimicrobials, their transformation by-products and antibiotic resistance determinants in treated wastewater

This study aimed to assess the possibility of using solar light-driven photolysis and TiO₂-based photocatalysis to remove (1) antibiotic residues, (2) their transformation products (TPs), (3) antibiotic resistance determinants, and (4) genes identifying the indicator bacteria in a treated wastewater (secondary effluent). 16 antimicrobials belonging to the different classes and 45 their transformation by-products were selected for the study. The most susceptible to photochemical decomposition was tetracycline, which was completely removed in the photocatalysis process and in more than 80% in the solar light-driven photolysis. 83.8% removal (on average) was observed using photolysis and 89.9% using photocatalysis in the case of the tested genes, among which the genes sul1, uidA, and intI1 showed the highest degree of removal by both methods. The study revealed that applied methods promisingly remove the tested antibiotics, their TPs and genes even in such a complex matrix including treated wastewater and photocatalysis process had a higher removal efficiency of antibiotics, TPs and genes tested. Moreover, the high percentage removal of the intI1 gene (>93%) indicates the possibilities of use of the solar light-driven photolysis and TiO₂-based photocatalysis in minimizing the antibiotic resistance genes transfer by mobile genetic elements.

Suspect screening of antimicrobial agents transformation products in environmental samples development of LC-QTrap method running in pseudo MRM transitions

The aim of the work was to develop a new HPLC-MS/MS method that allows for the simultaneous detection of antimicrobials agents (targeted analysis) and their transformation products (non-targeted analysis), which enabled the elucidation of their transformation pathways in the environment. Targeted analysis was performed for 16 selected antimicrobials agents (AMs) in wastewater collected at different stages of the treatment process and river water from sections before and after wastewater discharge. The samples were collected in the Łyna sewage treatment plant (Olsztyn, Poland) in three measuring periods at different seasons. Analytes were selected from tetracyclines, fluoroquinolones, β-lactams, macrolides, glycopeptides, lincosamides and synthetic antibiotics. As a part of the targeted analysis, 13 AMs were detected in wastewater samples, and 7 of them in river water samples. However, their presence and concentrations were closely related to the type of the sample and the season in which the sample was taken. The highest concentrations of AMs were detected in samples collected in September (max. 1643.7 ng L^-1 TRI), while the lowest AMs concentrations were found in samples collected in June (max. 136.1 ng L^-1 CLR). The total content of AMs in untreated wastewater was in the range of 1.42-1644 ng L^-1, while in the river water was for upstream 1.22-48.73 ng L^-1 and for downstream 2.24-149 ng L^-1. In the non-target analysis, 33 degradation products of the selected AMs were identified, and the transformation pathways of their degradation were speculated. In the course of the research, it was found that as a result of the processes taking place in wastewater treatment plant, the parent substances are transformed into a number of stable transformation products. Transformation products resulted from hydroxylation, ring opening, oxidation, methylation or demethylation, carboxylation, or cleavage of the CN bond of the parent AMs.

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.