Determination of phenolic constituents in citrus samples by on-line coupling of a flow system with capillary electrophoresis

Phenolic compounds extracted from different citrus were determined. Calibra tion, extraction, elution, and introduction into the sample vial was carrie d out automatically by a continuous flow system (CFS) coupled to capillary electrophoresis (CE) equipment via a programmable arm. The only manual oper ation was the centrifugation of the sample to remove the pulp. The supernat ant solutions were introduced into the CFS-CE system. A C-18 minicolumn cou pled into the CFS was used to perform cleanup of the samples. The analytes were eluted from the minicolumn using methanol. Quantitative analysis was c arried out by the standard addition method. The method presented allows a f ast, quantitative, and reproducible determination of six main phenolic comp ounds in citrus samples, with precision in the range of 3.0-6.5%, expressed as relative standard deviations.