Capillary Electrophoresis (CE)
Capillary electrophoresis (CE) is a separation method which is based on different velocities of ions in an electric field. The differences in the velocities or mobilities of ions are caused by different charge/radius ratios. The elementary parts of a CE system are a high voltage power supply, a source and destination vial, a fused silica capillary, electrodes and a detector. The source vial, destination vial and capillary are filled with an electrolyte such as an aqueous buffer solution. Application of high voltage up to 30 kV to the electrodes initiates an electric field. UV or fluorescence detectors are commonly used for detection of the analytes. The capillary is directly passed through the detector.
The advantages of CE are the very low injection volume (10 nl), the low limits of detection (pg-range) and the possibility of direct analysis of aqueous samples. Moreover the method shows almost no effects against matrix substances allowing analysis without laborious sample pretreatment. The conventional capillary zone electrophoresis (CZE) is limited to the separation of ionic compounds. However by use of micellar electrokinetic chromatography (MEKC) the spectrum of analytes can be extended to neutral and/or unpolar substances.
The capillary electrophoresis system G1600A from Agilent is available. The instrument is provided with an UV diode array detector and an autosampler.
- Organic acids