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Analysis of phloxine B and uranine in coffee by high-performance liquid chromatography and capillary zone electrophoresis after solid phase extraction cleanup
- Alcantara-Licudine, J.P., Bui, N.L., Kawate, M.K., Li, Q.X.
- Journal of agricultural and food chemistry 1998 v.46 no.3 pp. 1005-1011
- Coffea, coffee (beverage), roasting, dyes, toxic substances, chemical analysis, extraction, electrophoresis, high performance liquid chromatography
- A method was developed for the analysis of phloxine B and uranine, photoactive dyes being evaluated as fruit fly toxicants, in coffee cherries and green and roasted beans. The analytes were measured by high-performance liquid chromatography (HPLC) and capillary zone electrophoresis (CZE) using visible and fluorescence detectors after cleanup with disposable amino cartridges. A mixture of methanol (MeOH)/acetonitrile/n-butylamine (n-BA) (1/1/0.05) effectively extracted phloxine B and uranine from coffee cherries and green beans. The method yielded good recoveries of phloxine B (66-89%) and uranine (75-100%) at spike levels of 0.05-1.0 microgram/g from coffee cherries. Good recoveries of phloxine B (82-95%) and uranine (95-110%) were obtained from green beans at spike levels of 0.25-1.0 microgram/g. Addition of sodium hexametaphosphate in roasted beans prior to extraction with MeOH/acetone/n-BA (1/1/0.05) yielded good recoveries of phloxine B (72-77%) and uranine (79%) at spike levels of 0.5-1.0 microgram/g. HPLC and CZE are adequate for determining these analytes. The major advantages of CZE are short analysis time and use of inexpensive columns and aqueous buffer.