Integration of three-phase microelectroextraction sample preparation into capillary electrophoresis

•Three-phase electroextraction was coupled directly to capillary electrophoresis.•A new method for sensitive analysis of biogenic amines was developed.•Application of the method to urine shows promise for use in metabolomics. A major strength of capillary electrophoresis (CE) is its ability to inject small sample volumes. However, there is a great mismatch between injection volume (typically 0.9967) was observed for both model analytes. RSDs for peak areas in technical replicates, interday and intraday variability were all satisfactory, i.e., below 14%. 5-HT, Tyr and Trp spiked to human urine were successfully extracted and separated. These results underline the great potential of 3PEE as an integrated enrichment technique from biological samples and subsequent sensitive metabolomics analysis.