Technical data

8 Agilent 1290 Infinity LC System Manual and Quick Reference

1 Introduction to Ultra-High Performance 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

Short columns with sub-two-micron particles offer the opportunity to

dramatically reduce analysis time by increasing the flow rate without losing

separation performance.

2 Higher Resolution

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.

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.