Determination of phenolic acids in coffee by micellar electrokinetic chromatography

• Published in: Food chemistry Vol. 105; no. 4; pp. 1578 - 1582
• Main Authors: Risso, E.M, Peres, R.G, Amaya-Farfan, J
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2007; Elsevier
• Subjects: 5-caffeoylquinic acid; Biological and medical sciences; Caffeic acid; Capillary electrophoresis; Chlorogenic acid; chromatography; coffee beans; Coffee, tea and other stimulative beverage industries; extraction; Ferulic acid; food analysis; food composition; Food industries; Fundamental and applied biological sciences. Psychology; HPCE; isomers; MEKC; micellar electrokinetic chromatography; Phenolic acids; MEKC; Capillary electrophoresis; Chlorogenic acid; HPCE; Phenolic acids; Caffeic acid; Ferulic acid; Phenolic acid; Coffee; Cinnamic acid(4-hydroxy 3-methoxy); Chromatography
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2007.03.028

A seven-minute micellar electrokinetic chromatography analytical procedure capable of resolving the five principal phenolic acids in coffee, including the isomers of 5-caffeoylquinic acid (5-CQA), 4-CQA and 3-CQA, caffeic acid and ferulic acid is reported. The electrophoretic conditions consisted of an SDS (70 mM)-phosphate (17.6 mM)-methanol (5% v/v) buffer system, pH 2.5, 22.1 °C, −17 kV and detection at 325 nm. The Joule effect and the possible interactions between the buffer components and temperature with respect to peak quality, resolution and selectivity were assessed in the concentration range of 25–900 μg/mL. Performance evaluation of the system used a 3 3–7 factorial design at the 95% confidence level. The lowest correlation coefficient for linearity was 0.99888 for the 4-CQA. Limits of detection and quantification were 0.98 and 4 μg/mL. The method was tested with both green and roasted coffee beans using four systems of extraction.