engleski

Determination of anthelmintic pharmaceuticals in wastewater by solid-phase extraction and thin-layer chromatography

The present study describes development, optimization and validation of a method for determination of four structurally different anthelmintics (benzimidazole, diphenyl sulfide, imidazothiazole, hexahydropyrazine and tetrahydropyrimidine anthelmintic class) in water samples. The studied compounds were albendazole, febantel, levamisole, praziquantel and pyrantel pamoate. The method involves solid-phase extraction and preconcentration of the anthelminitics, separation by thin-layer chromatography (TLC) and quantification by video densitometry. TLC and preparative TLC separation was performed on Silicagel 60 F254 plates with chloroform–methanol-formic acid as mobile phase. Spots were detected and quantified at λ = 254 nm by videodensitometry. The method provides a linear response over the concentration range of 200–1500 μg/L, depending on the anthelmintic with the correlation coefficients 0.9888 in most cases except for albendazole (0.9634) and pamoic acid (0.9654) as a secondary component of pyrantel pamoate. Also, the method has revealed limits of detection (100–300 μg/L), good precision (intra and inter-day) with a relative standard deviation below 13% and recoveries above 95% for all investigated pharmaceuticals. The developed method has been successfully applied to the analysis of anthelmintics in production wastewater samples obtained from local pharmaceutical industry. In order to determine structures of two compounds detected by TLC of pyrantel pamoate, spots were separated by preparative TLC and structures of isolated samples were analysed using 1H and 13C NMR spectroscopy.

anthelmintics ; thin-layer chromatography ; NMR spectroscopy ; solid-phase extraction ; production wastewater

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