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  • Küçük Resim
    Öğe
    Application of cloud point extraction for residues of chloramphenicol and amoxicillin in milk samples by HPLC–DAD
    (Springer, 2022) Sürücü, Bilge; Ulusoy, Halil İbrahim; Ulusoy, Songül; Demir, Özge; Gülle, Sümeyra
    A pre-concentration and sensitive determination method for residues of Chloramphenicol (CLP) and Amoxicillin (AMX)in milk samples were developed based on cloud point extraction (CPE) and HPLC–DAD analysis. CLP and AMX moleculeswere extracted to surfactant phases of polyethylene glycol-6000 (PEG-6000) in the presence of pH 7.0 buffer andhigh electrolyte concentration. Experimental variables were examined and optimized such as concentration of electrolyteand surfactant, pH, incubation time, and diluting solvent. In the developed method, determination of CLP and AMX usingHPLC system was carried out by isocratic elution of water:acetonitrile (30:70) mixture. CLP and AMX antibiotic molecules were analyzed by considering peak area obtained by DAD detector at 273 nm and 276 nm, respectively. After optimizationexperimental variables, analytical signals were linear in the range of 10–900 ng mL− 1 and 25–1000 ng mL−1, respectively.The limit of detection values was calculated as 2.98 and 7.46 ng mL−1 while relative standard deviations (RSD %) were lowerthan 4.20% for 100 ng mL−1. Finally, the developed method was successively applied to cow milk samples.
  • Küçük Resim Yok
    Öğe
    Use of Fe3 O4 @MPTMS-Dithizone Magnetic Nanoparticles as Solid Phase Sorbent for Sensitive Analysis of Sibutramine Molecules in Herbal Slimming Products
    (Bentham Science Publishers, 2023) Demir, Özge; Ulusoy, Halil İbrahim; Polat, Ümmügülsüm; Ulusoy, Songül
    Background: A new enrichment and sensitive determination method, which includes HPLC-DAD analysis after Magnetic Solid Phase Extraction (MSPE), has been developed for trace analysis of Sibutramine molecules in herbal slimming products. Sibutramine is one of the most adulterated drug molecules in herbal products. Method: In the proposed method, Sibutramine molecules were pre-concentrated by using Fe3O4@MPTMS-Dithizone magnetic sorbent synthesized in our laboratory. Desorption of Sibutramine molecules from the sorbent phase was carried out by using acetonitrile: methanol (1:1) solvent in the presence of pH 8.0 buffer before chromatographic determinations. Results: Analytical parameters of the method, such as linear range, enrichment factor, and determination limit, were determined after optimizing experimental variables such as interaction time, desorption sol-vent, pH, etc. The sibutramine molecule was analyzed by isocratic elution of acetonitrile and KH2PO4 (pH 3.0, 0.05 M) (40:60) with a DAD detector at 223 nm wavelength. Limit of detection (LOD) value was calculated as 1.43 ng mL-1. Conclusion: Relative standard deviations (RSD) were below 3.20% for determinations of model solutions, including 100 ng mL-1 of Sibutramine. Finally, the developed method has been applied to herbal slimming tea samples with quantitative recovery experiments. © 2023 Bentham Science Publishers.