ANALYSIS OF BASIC PHARMACEUTICALS BY CAPILLARY ELECTROPHORESIS IN COATED CAPILLARIES AND ONLINE MASS-SPECTROMETRIC DETECTION

Basic pharmaceuticals were separated using capillary electrophoresis ( CE) and positively identified with the aid of an on-line coupled secto rfield mass spectrometer (MS). The coupling device consisted of a modi fied electrospray (ES) ion source with coaxial sheath liquid. The adap tation of the CE-conditions for the particular needs of ES-MS is discu ssed in brief. Applying volatile buffers of low ionic strength and usi ng uncoated capillaries in CE causes limited sample loadability, poor peak shapes and decreases resolution. The separation performance can b e significantly improved if the capillaries are coated with poly(ethyl ene glycol) (PEG) or poly(vinyl alcohol) (PVA). As extracted from the reconstructed ion current of the mass spectra, the baseline separated signals of structurally very similar compounds can be achieved. Signal s due to the protonated and Na+-attached molecules have been observed. Nozzle-skimmer dissociation may be a versatile tool for additional mo lecular structure information.