HPCE '90 Shigeru Terabe Himeji Institute of Technology Department of Material Science 2167 Shosha, Himeji 671-22 Japan
Building on the success of the first International Symposium on High-Performance Capillary Electrophoresis (HPCE '89) (1), organizers welcomed more than 560 scientists from more than 20 countries to HPCE '90, held January 29-31 in San Francisco. The meeting was chaired by Barry Karger from Northeastern University. In addition to 31 lectures and about 70 poster papers, the latest capillary electrophoresis (CE) instruments were exhibited. Three new complete CE systems from Isco, Spectra-Physics, and Waters, along with a modular system from Linear Instruments, were introduced. Five other commercially available CE systems—from Applied Biosystems, Beckman Instruments, BioRad Laboratories, Dionex, and Spectro Vision—were also displayed. Why is it that only American instrument companies are eager to place CE instruments on the market, and European and Japanese companies have failed to join them? Non-U.S. manufacturers are probably wondering about the future of CE in academia and industry. Symposium speakers discussed basic considerations for CE, detectors, applications, and MS interfaced with CE. The meeting began with an overview of electrophoretic methodologies by Pier Giorgio Righetti from the University of Milan. Righetti, a pioneer of isoelectric focusing (IEF) with Immobiline, which is an acrylamide derivative, talked about the excellent separability provided by IEF and related techniques 0003-2700/90/0362-605A/$02.50/0 © 1990 American Chemical Society
for proteins such as globulins and hemoglobins (2). Fred Régnier of Purdue University discussed the surface problem in CE from the viewpoint of a chromatographer. To completely suppress the effect of the surface charge of fused silica on the electroosmotic flow, a coating of >30 Â is necessary, according to Régnier. Otherwise, a tiny amount of charge could have a significant contribution to the zeta potential. Regnier's group has developed two types of polymer coatings for suppressing surface charge: polyethyleneimine bonded-phase coatings, which are positive under acidic conditions; and three dimensionally polymerized epoxy coatings, which are nonionic. Symposium chair Karger displayed ultra-high resolution spectra of poly-
FOCUS deoxyoligonucleotides obtained by capillary gel electrophoresis. The gel columns have a number of advantages: anticonvection medium, no electroosmotic flow, size selectivity, high efficiency/resolving power, focused injection, reproducibility, and stability. Karger's group has extensively studied the last two features, which are essential for capillary gel electrophoresis to be applicable to DNA sequencing. The group found that the reproducibility of the migration time of deoxyadenylic acid (dA) had a relative standard deviation (RSD) of 4.8% for poly(dA) 60 in gel columns prepared by two workers. Furthermore, the relative migration time of poly(dA) 50 to poly(dA)4o had an RSD of 0.07% from run to run and 0.7%
from batch to batch. He also stressed that when operated properly, gel columns can be used for more than 150 injections. The columns are highly efficient: A 50-cm gel column provides ~15 million theoretical plates for a 20-min run, thereby reducing diffusion coefficients of biopolymers to approximately 5 Χ 10" 8 cm2 β"1. Stellan Hjertén from the University of Uppsala discussed electrophoretic zone broadening. According to his equation, the optimal voltage, which gives the minimum plate height, can be calculated as a function of five parameters characteristic of solute, buffer, and capillary length. A typical example of the optimum field strength produced a calculated value of 450 V cm - 1 . Several speakers described recent advances in CE detectors. The use of a glass capillary with a rectangular cross section was described by Stanford's Richard Zare. Although such a capillary is fragile, it has the advantage over conventional fused silica capillaries of a large optical pathlength for absorbance detection. For example, a 50 μπι X 1000 Mm rectangular tube was ex perimentally measured to have a 10-fold increase in sensitivity (theoret ically, it can be as much as 20-fold) compared with a 50-μπι i.d. tube. Zare also described a continuousflow fraction collector for CE using a fused silica frit. The frit was set in a hole drilled on a capillary wall at a posi tion close to the end of the tube, per mitting current to flow through the frit. The fraction collector was used as an interface between CE and the detec tors, wherein the eluate from the capil lary was continuously transferred to a role of filter paper on a rotating wheel. Fluorescence was measured on the fil ter paper.
ANALYTICAL CHEMISTRY, VOL. 62, NO. 10, MAY 15, 1990 · 605 A
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Andrew Ewing from The Pennsylva nia State University used fused silica capillaries as small as 2 μτα ΊΑ. for a CE electrochemical detection system to determine catecholamines in the cyto plasm of single nerve cells. He can de termine dopamine down to levels of 3.4 Χ ΙΟ"6 Μ. The aim of this work is to produce a tiny sensor with separation capabilities for catecholamines. Edward Yeung from Iowa State Uni versity presented a new laser detection technique similar to indirect fluores cence. He measures the increase in flu orescence of an added fluorophore aris
Indiana University summarized recent advances in peptide and protein analy sis, which include optimizing separa tion conditions, pretreatment and preconcentration, and new fluorescent de rivatives for He-Cd laser-induced fluorescence. Novotony combined iso tachophoretic concentrating effect with CE as a preconcentration tech nique for dilute and small-volume sam ple solutions. A 120-nL solution of cy anogen-bromide-cleaved cytochrome c was concentrated to
