Simultaneous Determination of Alpha-Tocopherol and Alpha-Tocopheryl Acetate in Dairy Products, Plant Milks and Health Supplements by Using SPE and HPLC Method

• Published in: Food analytical methods 2017-12, Vol.10 (12), p.3886-3901
• Main Authors: Sunarić, Slavica, Lalić, Jelena, Spasić, Ana
• Format: Article
• Language: English
• Subjects: Acetic acid; Acetonitrile; Analytical Chemistry; Baby foods; Cartridges; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Colostrum; Dairy products; Ethanol; Fluorescence; Food Science; High-performance liquid chromatography; Infant formulas; Liquid chromatography; Microbiology; Pharmaceuticals; Plant-based beverages; Pretreatment; Tocopherol; Vitamin E
• ISSN: 1936-9751; 1936-976X
• DOI: 10.1007/s12161-017-0943-x

A solid phase extraction technique for sample cleanup and extraction of α-tocopherol and α-tocopheryl acetate is described and applied to their simultaneous HPLC analysis in dairy products, plant-based milks, infant formulas, and pharmaceutical colostrum. The proposed method includes sample pretreatment by using ethanol, followed by solid-phase extraction of the organic supernatant on C18 cartridges. The identification and quantification were done by reversed-phase HPLC with fluorescence detection (ex 295 nm, em 330 nm) for tocopherol and with UV detector set at 220 nm for tocopheryl acetate. The mobile phase consisted of 100% acetonitrile. The linear ranges were from 0.02–0.40 μg/mL (dairy products) and 0.50–5.00 μg/mL (plant milks, infant formulas, powdered products) for α-tocopherol and those of α-tocopheryl acetate were from 0.20–2.00 μg/mL (dairy products) and 1.00–10.0 μg/mL (plant milks, infant formulas, powdered products). The LOD and LOQ of α-tocopherol were 0.1 and 0.4 μg/mL, while those of the α-tocopheryl acetate were 2.0 μg/mL for LOD and 6.0 μg/mL for LOQ. The method gave extraction recoveries from 73–94% with RSDs values being 5–10%. This method is simple, SPE procedure is fast and HPLC analysis time is less than 10 min. The total time of performing analysis per sample is less than 1 h. The important advantage of the proposed method is the capability of determining and reporting α-tocopherol and α-tocopheryl acetate separately. Moreover, the developed method is suitable for fast screening of the synthetic form of vitamin E in dairy products, plant-based milks, infant formulas, and pharmaceutical colostrum.