title: Development and validation of an HPLC method for the simultaneous determination of tocopherols, tocotrienols and carotenoids in cereals after solid-phase extraction.
abstract: The increasing interest in antioxidant properties of cereal and cereal-based products has prompted the development of a simple and reliable HPLC method for the simultaneous determination of important phytochemicals like tocopherols (T), tocotrienols (T3) and carotenoids. Separation was carried out on a Nucleosil 100 C(18) column, 5 μm (250 mm × 4.6 mm) thermostated at 25 °C, using a linear gradient elution system starting with methanol and ending with a mixture of methanol-isopropanol-acetonitrile. All separated compounds including the internal standard (α-tocopherol acetate) were eluted within 16 min and detected by dual detection: fluorescence for tocopherols and tocotrienols at 290 nm excitation and 320 nm emission and UV-vis photodiode array detection for lutein and β-carotene at 450 nm. Detection limits ranged from 0.2 μg/g (β-carotene) to 1.60 μg/g (α-tocopherol). The intra- and inter-assay coefficients of variation were calculated by using cereals with different levels of lipophilic antioxidants. The extraction method involved sample saponification and clean-up by solid-phase extraction (SPE). The extraction recoveries obtained using OASIS HLB SPE cartridges and dichloromethane as eluent were in the range of 90.2-110.1%, with RSD lower than 10%. The method was successfully applied to cereals: durum wheat, bread wheat, rice, barley, oat, rye, corn and triticale.
authors.affiliation: Cereal Institute, National Agricultural Research Foundation, Thessaloniki, Greece.
authors.forename: Maria N
authors.initials: MN
authors.lastname: Irakli
authors.forename: Victoria F
authors.initials: VF
authors.lastname: Samanidou
authors.forename: Ioannis N
authors.initials: IN
authors.lastname: Papadoyannis
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000302:isolation & purification; D002338:Carotenoids / Q000032:analysis* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002523:Edible Grain / Q000737:chemistry*; D057230:Limit of Detection; D052616:Solid Phase Extraction; D024505:Tocopherols / Q000032:analysis* / Q000302:isolation & purification; D024508:Tocotrienols / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000975:Antioxidants; D024508:Tocotrienols; D002338:Carotenoids; D024505:Tocopherols