engleski

Determination of macrolide antibiotics, their intermediates and transformation products in solid environmental matrices

Among different types of emerging organic contaminants, antimicrobial compounds have come under special scrutiny, due to their possible contribution to the development and spreading of antibiotic resistance, which could be one of the most serious global threats to human health in the upcoming decades. As a consequence, numerous analytical methods for the determination of antimicrobials in environmental samples have been developed in the last 15 years. However, most of them are focused on parent compounds, or, at best, include some major metabolites, while the contribution of intermediates, byproducts and transformation products to the overall mass balance is much less understood. Moreover, the majority of the published methods aim to determine antimicrobials in water samples, typically only in the dissolved fraction, although some literature reports pointed out the importance of the sorption onto solid particles for several classes of antibiotics, such as fluoroquinolones and macrolides. The aim of this work was to develop a novel analytical method for determination of parent macrolide antibiotics (azithromycin, erythromycin, clarithromycin and roxithromycin), along with their metabolites, intermediates, byproducts and transformation products in solid environmental matrices, including sewage sludge and river sediment. Target compounds were extracted from the solid samples using pressurized liquid extraction and subsequently analysed by reversed-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The optimized method resulted in reliable determination of the target macrolides, with high recoveries and accuracies, even in the complex solid matrices. The relevance of the applied approach was demonstrated by the analysis of macrolide compounds in different types of the real solid samples, including sludge from the wastewater treatment plant of the city of Zagreb and sediment samples collected along the Sava River. Most of the target compounds were detected in the analysed samples with several azithromycin- and erythromycin-related compounds being rather abundant in sewage sludge and polluted river sediments. The total concentration of macrolides in sediment samples collected downstream of the pharmaceutical industry discharge exceeded 10 mg/kg. In addition, the results revealed the importance of metabolites and transformation products to the overall mass balance of macrolides in solid environmental samples.

Antibiotics ; Azithromycin ; Erythromycin ; Clarithromycin ; Macrolides ; Sludge ; Sediment ; Transformation products ; Liquid chromatography–tandem mass spectrometry

nije evidentirano