Theory Of Using Smaller Particles In Liquid Chromatography - Agilent Technologies 1290 Infinity LC System System Manual And Quick Reference

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Introduction to Ultra-High Performance Liquid Chromatography

Theory of Using Smaller Particles in Liquid Chromatography

Theory of Using Smaller Particles in Liquid Chromatography
Introduction
In 2003, Agilent introduced the first commercially available porous silica
columns with 1.8 µm particles. These were the first in a class of columns
which has become known as 'sub-two micron' or STM columns. For use with
the Agilent 1200 Series Rapid Resolution LC system, launched in 2006, these
packing materials were introduced in ZORBAX RRHT columns capable of
withstanding 600 bar pressure. In 2009 the range was extended to include
RRHD columns capable of routine use at 1200 bar pressure to support the
introduction of the Agilent 1290 Infinity LC System with its extensive
operating power range up to 1200 bar pressure and 5 ml/min flow rate.
These sub-two micron (1.8 µm) particle size columns can be used in pursuit of
two main objectives:
1 Faster Chromatography
2 Higher Resolution
The pressure needed to drive solvent through a column containing STM
particles rises rapidly as flow rate is increased for faster separations and very
rapidly as the length of the column increases for more resolution. Thus the
acceptance of STM columns has been synonymous with the development of
UHPLC systems – that is HPLC systems that offer higher pressures than the
400 bar norm that was extant since the early days of HPLC. Ultra-High
Performance (or Ultra-High Pressure) LC systems also offer low delay volumes
and the fast data collection required for narrow peaks from fast or high
resolution chromatography. The Agilent 1290 Infinity LC is a landmark in
UHPLC as it is the first system that can completely cover and extend upon all
the disparate performance ranges of UHPLCs pre-existing on the market.
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Short columns with sub-two-micron particles offer the opportunity to
dramatically reduce analysis time by increasing the flow rate without losing
separation performance.
Long columns with sub-two-micron particles provide higher efficiency and
therefore higher resolution, required for the separation of complex samples.
Lower dispersion also means less dilution of the analyte peaks and
consequent sensitivity gains, particularly for LC/MS.
Agilent 1290 Infinity LC System Manual and Quick Reference