Trace Determination of Macrolide and Sulfonamide Antimicrobials, a Human Sulfonamide Metabolite, and Trimethoprim in Wastewater Using Liquid Chromatography Coupled to Electrospray Tandem Mass Spectrometry

Abstract

An analytical method has been developed and validated for the simultaneous trace determination of four macrolide antibiotics, six sulfonamides, the human metabolite N4-acetylsulfamethoxazole, and trimethoprim in wastewater. The method was validated for tertiary, secondary, and-unlike in previously published methods-also for primary effluents of municipal wastewater treatment plants. This wide range of application is necessary to thoroughly investigate the occurrence and fate of chemicals in wastewater treatment. Wastewater samples were enriched by solid-phase extraction, followed by reversed-phase liquid chromatography coupled to tandem mass spectrometry using positive electrospray ionization. Recoveries from all sample matrixes were generally above 80%, and the combined measurement uncertainty varied between 2 and 18%. Concentrations measured in tertiary effluents ranged between 10 ng/L for roxithromycin and 423 ng/L for sulfamethoxazole. Corresponding levels in primary effluents varied from 22 to 1450 ng/L, respectively. Trace amounts of these emerging contaminants reach ambient waters, since all analytes were not fully eliminated during conventional activated sludge treatment followed by sand filtration. In the case of sulfamethoxazole, the amount present as human metabolite N4-acetylsulfamethoxazole had to be taken into account in order to correctly assess the fate of sulfamethoxazole in wastewater treatment.

An overview of analytical methodologies for the determination of antibiotics in environmental waters

“…When the wastewater sample was analyzed, lower volumes can be used for preconcentration because antibiotics occur there at higher concentration levels. For example, in the evaluation of efficiency of treatment process in WWTP, only 50 or 100 mL of influent and 250 mL of effluents from WWTPs were used [7,24,29,33]. However, nowadays, the trend is using smaller amount of sample allowing fast sample preparation step and thus shorter time of analysis or even the direct injection of water sample on LC.…”

“…IS could be used as surrogate standards-they are added prior to the enrichment to assess possible losses during the analytical procedure or like instrumental standards that are added to the final extracts prior to measurement. While the surrogate standards are used for the quantification, the instrumental standards are used to check the instrument performance during measurement [7].…”

“…Structurally related compounds e.g., kitasamycin [17], spiramycin [9], josamycin [5,7,24] or oleandomycin [5] were also employed. Table 8 HPLC analytical methods for the determination of MLs.…”

“…Wastewater treatment plants (WWTPs) are considered to be major contributors of presence of pharmaceuticals in the environment. Pharmaceuticals along with their metabolites have been found in the effluents from WWTPs [7][8][9]. Therefore they can reach the surface and groundwater.…”

Aspectos analíticos e regulatórios na determinação de resíduos de macrolídeos em alimentos de origem animal por cromatografia líquida associada à espectrometria de massas

“…Em geral, os macrolídeos apresentam pK a entre 7,1 e 9,9. 10 Alguns macrolídeos são sensíveis a baixo pH e sofrem degradação em condições ácidas. 1 A eritromicina é um dos macrolídeos mais importantes.…”