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Optimized QuEChERS (quick, easy, cheap, effective, rugged and safe) method of sample preparation was employed for five selected pharmaceutical compounds on its advantage of simplicity, less extraction solvent and extraction time. Different parameters affecting the extraction efficiency of the target analyte was optimized. Since QuEChERS was developed for pesticides, uses of the method for pharmaceuticals need modification and evaluation of different parameters. Clean-up sorbents were evaluated for their matrix effect removal after extraction and a combination of d-SPE sorbent, MgSO4, PSA, C18 and diatomaceous earth found to be selective clean-up sorbent for the targeted compounds. The addition and amount of diatomaceous earth and EDTA during the clean-up and extraction steps, respectively, were also examined and the amount was optimized. Solvent type and composition, salt type and extraction time were also optimized and methanol, MgSO4 with NaCl salt and 5 min extraction time was obtained. The method was successfully applied to different vegetable samples collected from Addis Ababa, Ethiopia and Johannesburg, South Africa (carrot, cabbage and lettuce) and none of the target analytes were found in the sample investigated. The matrix effect study on vegetable samples collected was found very high that suppresses the signal during analysis. [ABSTRACT FROM AUTHOR]

Pharmaceutical consumption is increasing worldwide as it is essential to treat and prevent health issues but they end up in the environment. However, in many African countries like Ethiopia, the status of these compounds in various environmental samples is not very well known. In this study, a simple method for the extraction and determination of thirteen pharmaceutical compounds of different therapeutic classes in water samples using solid-phase extraction and HPLC-DAD was developed. Different parameters affecting extraction were optimised and obtained as hydrophilic-lipophilic balance (HLB) extraction cartridge, water sample pH of 5, elution solvent of 2% formic acid in water with methanol (20:80%, v/v), a sample volume of 150 mL and addition of 0.5% w/v EDTA in the sample. The limits of detection and quantification of the optimised method were in the range of 0.1–0.8 µg/L and 0.2–2.6 µg/L, respectively. The relative recovery in the spiked environmental water sample was in the range of 70–117% except for amoxicillin and acetylsalicylic acid in influent wastewater. The precision for all ranged from 0.3 to 11%. The proposed method was successfully tested for the detection and quantification of different environmental water samples collected from Addis Ababa, Ethiopia. Trimethoprim, caffeine and albendazole concentrations of 7.8 (1.1), 3.2 (0.4) and 2.1 (0.1) µg/L were quantified in hospital wastewater, respectively. The concentration of norfloxacin was found to be below the limit of quantification in the same water. Trimethoprim and ciprofloxacin were also found in the sewage treatment plant influent sample at a concentration of 0.5 (0.02) and 0.3 (0.01) µg/L, respectively. [ABSTRACT FROM AUTHOR]