Comparison between titrimetric and spectrophotometric methods for quantification of vitamin C.
Vitamin C is usually quantified by titrimetric or chromatographic methods. However, these methods have limitations: food color interferes with the titrimetric method and the chromatographic method is costly. The aim of this study was to compare a spectrophotometric method, based on reduction of cupric ions in the presence of cuproine complex, with a titrimetric method, based on reduction of 2,6-dicholorophenolindophenol. Linearity, precision, accuracy, and limits of detection (LOD) and quantification (LOQ) were evaluated using a standard vitamin C solution. Both methods were also applied for AA quantification in industrialized orange and pineapple juices. The methods were precise and accurate when applied to the standard solution. The spectrophotometric method was more sensitive, with lower values for LOD (0.002mgmL-1) and LOQ (0.010mgmL-1), and more accurate with error less than 5% while results from the titrimetric method were affected by the juice color, which generated errors in excess of 15%.
Integrated College Maria Imaculada, R. Paula Bueno, Centro, Postal Code: 13.080-040, Mogi Guaçu, São Paulo, Brazil.
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da Silva
Exact Science and Technology Department, Santa Cruz State University, R. Jorge Amado, km 16, Salobrinho, Postal Code: 45.662-900 Ilhéus, Bahia, Brazil.
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Aguiar-Oliveira
Food Engineering Department, Faculty of Animal Husbandry and Food Engineering, University of São Paulo, Campus Pirassununga, Av. Duque de Caxias Norte, 225, Campus da USP, Postal Code: 13635-900, Pirassununga, São Paulo, Brazil.
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Mazalli
Food Engineering Department, Faculty of Animal Husbandry and Food Engineering, University of São Paulo, Campus Pirassununga, Av. Duque de Caxias Norte, 225, Campus da USP, Postal Code: 13635-900, Pirassununga, São Paulo, Brazil.
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Kamimura
Integrated College Maria Imaculada, R. Paula Bueno, Centro, Postal Code: 13.080-040, Mogi Guaçu, São Paulo, Brazil; Federal Institute of São Paulo, Campus Capivari, Av. Dr. Enio Pires de Camargo, 2971, São João Batista, Postal Code: 13360-000, Capivari, São Paulo, Brazil; Food Department, Technical College of Campinas, University of Campinas, R. Jorge Figueiredo Corrêa, Parque Taquaral, Postal Code: 13087-261 Campinas, São Paulo, Brazil. Electronic address: ratafta@yahoo.com.br.
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Maldonado
D031230:Ananas; D001205:Ascorbic Acid / Q000032:analysis*; D002623:Chemistry Techniques, Analytical / Q000379:methods* / Q000592:standards; D032084:Citrus sinensis; D000067030:Fruit and Vegetable Juices / Q000032:analysis*; D057230:Limit of Detection; D013053:Spectrophotometry / Q000379:methods / Q000592:standards; D017186:Titrimetry / Q000379:methods / Q000592:standards
D001205:Ascorbic Acid
2,6-Dichlorophenolindophenol; 2,6-Dichlorophenolindophenol (PubChem CID:13726); Ascorbic acid; Ascorbic acid (PubChem CID: 54670067); Cuproine; Cuproine (PubChem CID: 8412); Dehydroascorbic acid (PubChem CID:440667); Juice; Oxalic acid (PubChem CID: 971); Spectrophotometry; Titration