Genentech (S. San Francisco), Randall Nielsen of Eli Lilly ( I n d i a n a p o l i s ) , Steve Fazio of Sandoz Research Insti tute (E. Hanover, N J ) , Ferenc Kilar of Uppsala University, and Louis Yu of R. W. Johnson Pharmaceutical Re search Institute (Raritan, N J ) . Ewing described the use of CE in a study of single functioning nerve cells. Cytoplasmic samples are e x t r a c t e d from single cells, and electrophoretic separations s u b s e q u e n t l y are per formed using amperometric or mass spectrometric detection. T h e system p e r m i t s d e t e c t i o n of s u b a t t o m o l e amounts of easily oxidized neurotrans mitters in picoliter volumes. Gassmann, Hancock, Fazio, Neilsen, Yu, and Kilar described methods for analyzing peptides synthesized using r e c o m b i n a n t D N A technology, for which small variations in the primary or secondary structure of the peptide can produce a small change in the over all charge on the molecule. In the past, said Hancock, electrophoretic tech niques such as SDS electrophoresis and IEF were used to separate protein vari ants a n d i m p u r i t i e s , b u t c o m p a r e d with liquid c h r o m a t o g r a p h i c tech niques, traditional slab gel electropho retic techniques are difficult to quantitate. CE, however, combines the power of electrophoresis with the instrumen tal capabilities of c h r o m a t o g r a p h i c methods and can be applied to such protein p h a r m a c e u t i c a l s as h u m a n growth hormone, tissue plasminogen activator, and 7-interferon. Because of their different separation mechanisms, CE and LC can be viewed as comple mentary techniques in the biotechnol ogy laboratory. HPCE/MS The symposium wound u p with two sessions on combining CE with mass spectrometric detection. Instrumenta tion and applications of this new tech nique were discussed by Richard Smith of Pacific N o r t h w e s t L a b o r a t o r y (Richland, WA), Jack Henion of Cor nell University, Herbert Hill of Wash ington State University, Richard Caprioli of the University of Texas, and Arthur Moseley of the University of North Carolina at Chapel Hill. Smith described his work in combin ing CE with MS using an electrospray ionization interface. Capillary zone electrophoresis (CZE) a n d capillary isotachophoresis have already been successfully interfaced, said S m i t h , and extension to I E F , MECC, and polyacrylamide gel-filled capillaries appears feasible. Detection limits of a few attomoles have been achieved, and proteins of up to 75,000 daltons can be separated and determined. T h e major
difficulty appears to be loss of separa tion efficiency because of protein inter actions with surfaces of the capillary, leading to higher detection limits for large biomolecules. A system for C Z E / M S / M S with at mospheric pressure ionization was de scribed by Henion, who has used it to analyze synthetic peptide mixtures and tryptic digests and to determine sulfo nated azo dyes isolated from wastewa ter samples. T h e mild conditions of at mospheric ionization allow accurate molecular weight determination, and tandem M S provides sequence infor mation for each peptide. T h e detection limit of the system is in the low attomole-to-femtomole range. Hill described results of initial inves tigations of the use of ion mobility spectrometry as a detection method for CE. Electrified spray ionization meth ods such as electrospray and corona spray are incorporated into the CZE/ ion mobility detection system. Finally, both Caprioli and Moseley described the combination of CZE with continuous-flow fast atom bombard ment (CF-FAB) M S for analysis of peptide mixtures. In Caprioli's system, a fused-silica capillary column is con nected to the CF-FAB probe via an in terface t h a t allows a total flow of ~ 5 μΐι/πιΐη into the mass spectrometer. Peptide solutions are loaded pneumat ically onto the capillary, and the de sired mass range is scanned with a mag netic mass spectrometer. Moseley's system, developed with Jorgenson and Ken Tomer of the Na tional I n s t i t u t e of E n v i r o n m e n t a l Health Sciences (Research Triangle Park, NC), uses a set of coaxial 10-μπι capillaries t o independently deliver the microcolumn effluent and the FAB matrix directly to the FAB probe tip face. T h e system was designed to mini mize band broadening and preclude any deleterious effects of the FAB ma trix on the separation process. It has been used with both CE and capillary LC to obtain on-the-fly F A B / M S spec tra of several analyte classes, including peptides, and can be used to obtain se q u e n c e information of subpicomole amounts of proteins. T h e next CE meeting, to be chaired by Karger, is scheduled for J a n u a r y 2 9 31, 1990, in San Francisco. T h e organ izers had originally planned the next meeting for February 1991 to give the field a chance to mature, but the im pressive a t t e n d a n c e a t H P C E '89 prompted t h e m to schedule an interim meeting. Given the anticipated growth of this technique and its increasing use in solving bioanalytical p r o b l e m s , H P C E '90 should be even better than H P C E '89. Mary Warner
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