TuP-12
DEVELOPMENT OF A COMPACT CAPILLARY SEPARATION INTERFACE
Michael Morris, Roger Giles, Steve Lane*, Robert Boughtflower*, Clare Paterson*+ and Tim Underwood*
VG Organic, Tudor Road, Altrincham, Cheshire WA14 5RZ, UK
*Glaxo Wellcome, Gunnels Wood Road, Stenenage, Hertfordshire SG1 2NY, UK
+Department of Biological Sciences, Manchester Metropolitan University, Manchester M1 5GD, UK
In recent years there has been considerable interest in the interfacing of low flow-rate separation techniques (e.g. capillary electrophoresis (CE), capillary electrochromatography (CEC)) to mass spectrometry. CE and CEC both rely on an electrical field being generated along the length of a column in order to generate liquid flow. It is preferable in such instances to generate as high a field strength as possible suggesting that the shorter the length of the column the better for a fixed applied potential. Flow rates used in CE and CEC typically in the 100 nanolitres per minute range, often requiring the use of a sheath solvent if the separatory technique is to be coupled to a mass spectrometer via an electrospray-type interface. One inherent problem that arises when coupling two separate instruments together when the flow rates are very small is that the size of any dead volumes becomes significant and may seriously degrade the separation and thus the performance of the combined technqiue. One possible solution to both these above problems is to perform a short column separation (<50cm) that terminates at the end of the probe, whilst still providing a method of introducing the sample of interest into the column without the need for long lengths of unnecessary capillary.
We have developed an arrangement in which the whole of the CE and CEC analyses, including the injection of the sample and the separation of the components of interest, can be performed within the confines of a normal probe, eliminating the need for interconnecting two separate analytical instruments.We have used this device interfaced to a quadrupole mass spectrometer via an electrospray inetrface, and initial experiments on short packed columns used for CEC in this arrangement have shown excellent separations yielding up to >100,000 theoretcial plates per metre working at a field strength of approximately 600V/cm. Details of the interface and performance will be presented.