Exciting Science at 2007 MSB Symposium
The annual Microscale BioSeparations (MSB)
meeting series, which started as the HPCE (High
Performance Capillary Electrophoresis), provides
a focused forum for improving separations technology
and illustrating the utility via applications reports. If the
basic science of these disciplines is to progress, scientists
will need even higher resolution and sensitive detection.
Half of the dual track program was chip-related, but this
article will focus on advances in capillaries and columns.
While a more detailed report appears in the April 2007
issue of American Biotechnology Laboratory, this piece will
provide a basic overview of what proved to be an exciting,
highly worthwhile scientific conference.
LC column technology continues along divergent
paths. According to Professor Jim Jorgensen of the
University of North Carolina at Chapel Hill, North
Carolina, the optimum size of the column packing
depends upon the mole weight of the analyte. For small
molecules, the optimum is in the range of 1 to 1.5 um.
These can be purified by hydrodynamic chromatography
using a packed bed. For proteins, the optimum diameter
may be about 0.5 um.
Prof. Tanaka of Kyoto institute of Technology, Kyoto,
Japan, compared monolithic silica with packed beds.
Neglecting differences in selectivity, RPLC columns with
packed beds offer the best performance for separations
requiring about 20,000 plates or less. This limit can be
extended to about 35,000 plates, if the available pressure
is increased from 6,000 psi to 15,000 psi.
However, Professors B. L. Karger (Northeastern
University, Boston), Frank Svec (University of California,
Berkeley) and Joe Pesek (California State University at
San Jose) offered still another alternative: Wall coated
open tubular capillaries with id about 10 to 20 microns.
The stationary phase is bonded to fused silica capillaries
through epoxy or olefinic coupling.
Dr. Gary A. Valaskovic, founder and president of New
Objective of Woburn, MA, explained that the firm celebrated
its 10th anniversary at the MSB meeting. New
Objective’s fittings for small capillary LC are based upon
avoiding movement of the ends of the tubing as the tubing
is clamped in place. The capillaries are inserted into
transparent fluoropolymer guides, which position the
tubing with an alignment of better than 10 microns.
Valco Instruments of Houston showed a range of
products for capillary LC based upon 360 um OD
capillaries of fused silica, nickel, or PEEK. Valco has even
made a composite nickel/PEEK tube that works with the
fittings at pressures of 30,000 psi. Fittings include union,
“T”, cross and plug. These novel products should make it
possible for many more scientists to explore capillary
liquid phase separations. The tools are available to conveniently
explore the practical pressure limits of HPLC.
Micrhrom Bioresources of Auburn, CA introduced
an alternative technology called axial
desolvation, vacuum assisted nano capillary
electrospray (ADVANCE) that provides nanospray performance
at a flow rate of 0.2 to 100 ul/min, which is in
the normal range for ESI interfaces. The tornado effect
created by the ADVANCE interface strips the solvent
ions to the perimeter of the cone while focusing the heavier
analyte ions on the ion inlet. An automated capLCADVANCE/
MS can analyze 50 to 150 proteomic samples
in 24 hours with attomole to picomole LOD.
In a vendor seminar, Dr. Gerard Rozing led off with an
introduction of the HPCE and microfluidics products
developed by Agilent, including the Bioanalyzer and
Agilent 3D CE. Agilent continues to develop these as
shown by the cooperation with Picometrics, for adding
LIF to the 3D.
In the world of micro analysis, CE seems to be ideal as
an inlet for MS. Peaks are sharp in time, and the liquid
load on the MS is ve ry low. Beckman organized a vendor
seminar on CE-MS that featured a report by Professor
Christian Neusuess of Aalen University, Aalen, Germany,
who described CE-MS of natural products. One example
is glucosinolates, which are so small and polar with retention
in HPLC.
Prof. Mehdi Moini of the University of Texas in Austin
rapidly reviewed his work with CE-MS of single cells
using 10 um diameter capillaries on a chip. He
described a novel porous side arm for providing electrical
conduction for the ESI tip. Agilent Technologies has
licensed a new protein preparation system that provides
easy fractionation of protein samples with a resolution of
0.1 to 0.5 pI. The Agilent 3100 “Offgel Fractionator”
provides pI based fractionation of proteins and peptides
compatible with recove ry by syringe for manipulation.
Microscale BioSeparations ’07 drew 270 scientists from
21 countries to Vancouver in January. The program consisted
of 80 lectures in dual sessions and almost 200
posters. Professor Robert T. Kennedy of the University of
Michigan was the overall chair. With the help of the
Permanent Committee and 22 members of the Scientific
Advisory Committee, they deserve credit for organizing
an outstanding scientific program. Erin Kelch of CaSSS
deserves special thanks for organizing the meeting.
The next MSB meeting is March 9-13, 2008 in Berlin.
More information is available at www.msb2008.org. In
2009, MSB will return to North America. Please monitor
www.casss.org.
Other meetings of interest: APCE 2007,
Dec. 16 to 19, 2007 at the International Convention
Center in Singapore. See www.sicc2007.org.
Also: ISPPP 2007 (International Symposium on the Separation of
Peptides, Proteins and Polynucleotides), Oct. 21-24,
2007 in Orlando, Florida. See www.isppp.org.
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