Browsing by Author "Apak, Resat"

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Combined Spectroscopic and Chromatographic Techniques Augmented With Chemometrics for the Authentication of Black Cumin ( Nigella Sativa L . ) Seed Oil
(Academic Press inc Elsevier Science, 2024) Karaman Ersoy, Şeyda; Ersoy, Seyda Karaman; Kaya, Elif Nilay; Senol, Onur; Apak, Resat; Temel Eczacılık Bilimleri Bölümü
Edible oils adulteration has a great concern because of its health and economical effects. Black cumin seed oils (BCSOs) are one of the most adulterated edible oils. In this case, the purpose of this research was to investigate authenticity of commercial BCSOs by spectroscopic and chromatographic techniques combined with orthogonal partial least square -discriminant analysis (OPLS-DA) and hierarchical cluster analysis (HCA). Sixteen commercial BCSO samples (100 % pure-certified and other BCSOs), potential blending oils (sunflower, corn, and soybean oils), and twenty-one synthetically adulterated BCSO samples blended with sunflower (SFO), corn (CO), and soybean (SBO) oils at levels of 5 %, 10 %, 15 %, 20 %, 30 %, 40 %, and 50 % (v/v) were analysed. Screening of potential fingerprinting markers such as thymohydroquinone (THQ), thymoquinone (TQ), carvacrol (CRV), tocopherol isomers ( alpha-, gamma -, and delta -), as well as total antioxidant capacity and phenolic content analysis were carried out utilizing spectrophotometric CUPRAC, ABTS, and Folin Ciocalteu ' s assays. Commercial pure and fraudulent BCSOs and synthetically adulterated samples were successfully classified in OPLS-DA graphs with 95 % confidence level. Even to five percent detection limit for SFO, CO and SBO adulteration were prominently monitored. In consequence, the proposed spectroscopic and chromatographic methods seem to be a practically applicable, sensitive and versatile protocol that can be used as an alternative fingerprinting procedure to determine adulteration of commercial BCSOs.
Citation - WoS: 2
Citation - Scopus: 2
Preparation and Application of Caffeic Acid Imprinted Polymer
(Tubitak Scientific & Technological Research Council Turkey, 2023) Karaman Ersoy, Şeyda; Tutem, Esma; Baskan, Kevser SoeZGEN; Apak, Resat; Temel Eczacılık Bilimleri Bölümü
In the present study, molecularly imprinted polymers were synthesized using caffeic acid (CA) as a template molecule and then used for the extraction of CA and chlorogenic acid (CLA) from complex matrices. Syntheses were carried out in tetrahydrofuran as porogenic solvent using 4-vinyl pyridine, methacrylic acid, acrylamide, and 1-vinyl imidazole as monomers, ethylene glycol dimethacrylate as crosslinker and 2,2'-azobisisobutyronitrile as initiator. In polymerization processes, different ratios of the template:monomer:crosslinker (T:M:CrL) were used to obtain the most suitable polymer. Caffeic acid:4-vinylpiridine:ethylene glycol dimethacrylate's 1:4:16 mole ratio of MIP was determined as the most convenient polymer for CA recognition. In addition, nonimprinted polymers (NIPs) without templates were prepared. Dynamic and static adsorption tests were applied to determine the absorption features of the NIPs and CA-MIPs. Separation and purification studies of CA and CLA were performed with molecular imprinted solid phase extraction (MISPE) application. All steps of MISPE (loading, washing, elution) were optimized by HPLC analysis.