title: A validated solid-liquid extraction method for the HPLC determination of polyphenols in apple tissues Comparison with pressurised liquid extraction.
abstract: A solid-liquid extraction procedure followed by reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a photodiode array detector (DAD) for the determination of polyphenols in freeze-dried apple peel and pulp is reported. The extraction step consists in sonicating 0.5g of freeze-dried apple tissue with 30mL of methanol-water-acetic acid (30:69:1, v/v/v) containing 2g of ascorbic acid/L, for 10min in an ultrasonic bath. The whole method was validated, concluding that it is a robust method that presents high extraction efficiencies (peel: >91%, pulp: >95%) and appropriate precisions (within day: R.S.D. (n = 5) <5%, and between days: R.S.D. (n = 5) <7%) at the different concentration levels of polyphenols that can be found in apple samples. The method was compared with one previously published, consisting in a pressurized liquid extraction (PLE) followed by RP-HPLC-DAD determination. The advantages and disadvantages of both methods are discussed.
authors.affiliation: Departamento de Química Analítica, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea, P.O. Box 644, E-48080 Bilbao, Spain.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Alonso-Salces
authors.forename: Alejandro
authors.initials: A
authors.lastname: Barranco
authors.forename: Edurne
authors.initials: E
authors.lastname: Corta
authors.forename: Luis A
authors.initials: LA
authors.lastname: Berrueta
authors.forename: Blanca
authors.initials: B
authors.lastname: Gallo
authors.forename: Francisca
authors.initials: F
authors.lastname: Vicente