title: Determination of vitamin C in foods: current state of method validation.
abstract: Vitamin C is one of the most important vitamins, so reliable information about its content in foodstuffs is a concern to both consumers and quality control agencies. However, the heterogeneity of food matrixes and the potential degradation of this vitamin during its analysis create enormous challenges. This review addresses the development and validation of high-performance liquid chromatography methods for vitamin C analysis in food commodities, during the period 2000-2014. The main characteristics of vitamin C are mentioned, along with the strategies adopted by most authors during sample preparation (freezing and acidification) to avoid vitamin oxidation. After that, the advantages and handicaps of different analytical methods are discussed. Finally, the main aspects concerning method validation for vitamin C analysis are critically discussed. Parameters such as selectivity, linearity, limit of quantification, and accuracy were studied by most authors. Recovery experiments during accuracy evaluation were in general satisfactory, with usual values between 81 and 109%. However, few methods considered vitamin C stability during the analytical process, and the study of the precision was not always clear or complete. Potential future improvements regarding proper method validation are indicated to conclude this review.
authors.affiliation: Centro de Química da Madeira (CQM), Centro de Ciências Exactas e da Engenharia da Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal.
authors.forename: Vítor
authors.initials: V
authors.lastname: Spínola
authors.affiliation: Centro de Química da Madeira (CQM), Centro de Ciências Exactas e da Engenharia da Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal; Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas S/N, E-23071 Jaén, Spain.
authors.forename: Eulogio J
authors.initials: EJ
authors.lastname: Llorent-Martínez
authors.affiliation: Centro de Química da Madeira (CQM), Centro de Ciências Exactas e da Engenharia da Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal. Electronic address: castilho@uma.pt.
authors.forename: Paula C
authors.initials: PC
authors.lastname: Castilho
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005504:Food Analysis / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D011786:Quality Control; D014815:Vitamins / Q000032:analysis*
chemical_list: D014815:Vitamins; D001205:Ascorbic Acid
keywords: Foodstuffs; HPLC; Method development; Method validation; Vitamin C