Many applications, however, can be accomplished with a single, well-engineered, component-based HPLC system. To limit oneself
to a highly restrictive system in today's ever-changing laboratory environment is not ideal. One may need to add different
detectors to the system to accomplish a new task or one may add switching valves to increase throughput even more. A modular
system that is based on sound engineering principles includes pumping options that deliver a wide flow-rate range with precise
delivery resolution, incorporates an accurate and precise autosampler that provides excellent carryover performance, and has
the accessories necessary for continued expansion offers superior performance for UFLC and traditional HPLC.
Conclusion
One can address the problem of increased system pressure that results from very small particle-size columns by choosing a
well-packed mid-size particle material instead. These mid-size columns offer similar performance, yet generate less than half
of the back pressure compared with commercially available sub-2-μm particle columns. Coupling these mid-size particle columns
with good chromatographic techniques and a well-engineered high-performance liquid chromatography system enables users to
shorten analysis time drastically, without the consequence of extreme pressures. The right columns and techniques also permit
users to maintain high separation efficiency and fulfill system-performance needs such as reproducibility, reduced carryover,
and durability. The end result is high-quality data obtained without compromises.
The goal of fast liquid chromatography is not high pressure; high pressure is simply a consequence of using a column packed
with a small particle (sub 2 μm). The goal is increased throughput (i.e., analyzing more samples per day, per hour or per
minute). To achieve high throughput, the run time of a single chromatogram must be optimized, and the total cycle time of
the assay must be examined and optimized as well. After all, what good is a 30-s separation if it takes 45 s to inject the
next sample?
Curtis R. Campbell, PhD*, is a high-performance liquid chromatography (HPLC) product manager, and Susan Steinike is an HPLC senior product specialist at Shimadzu Scientific Instruments, 7102 Riverwood Dr., Columbia, MD 21046, tel. 800.477.1227,
crcampbell@shimadzu.com.
*To whom all correspondence should be addressed.
Reference
1. Butchart, et al., "Do Sub 2 μm Particles Offer the Best Performance for Short Fast Gradients?" in poster session presented
at the 31st International Symposium on High Performance Liquid Phase Separations and Related Techniques (Ghent, Belgium, June 17–21, 2007)
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