The Column - March 2008 - (Page 15)

March 2008 www.thecolumn.eu.com The Column Tipler A Holistic Approach to Increasing Analytical Throughput on a Modern Gas Chromatograph Andrew Tipler, PerkinElmer Inc., Waltham, Massachusetts, USA. Introduction Gas chromatography (GC) recently celebrated its 50th anniversary. Although there have been many advances in GC over these years, the fundamental technology essentially remains the same: a sample is introduced through an injector into a carrier gas that transfers it into the separation column and onto a detector. A data acquisition system is used to monitor and process the component peaks detected as they elute. The use of GC instruments is now ubiquitous throughout analytical laboratories across a wide variety of industries for many types of samples. Over the years, GC instruments have evolved into designs that are reliable, easy-to-use and productive. The advent of microprocessors was a major revolution in this field and many tedious and laborious processes associated with running GCs and extracting meaningful data suddenly became much easier and quicker — sometimes even to the point of almost eliminating the need for the analyst altogether. On these automated systems, the rate determining factor in running samples is often no longer the user and analytical throughput is purely dependent on the speed of the instrumentation to deliver the results. There have been many articles and papers on the subject of high-speed GC where, in some instances, chromatographic separations taking less than one second have been demonstrated. While in itself this is impressive, it does not fully reflect the ability of the chromatograph to quickly process an entire batch of samples. Other factors contribute to the overall analysis time as shown in Figure 1. This figure highlights some of the activities occurring in between successive chromatograms. As the chromatography time is reduced, this “non-productive time” becomes a much Author: Andrew Tipler E-mail: Andrew.Tipler@perkinelmer.com more significant factor in the overall throughput of the system. To increase sample throughput, it is also important to address these steps. In fact, any reduction in the lost time between chromatograms will benefit any GC method, not just those using fast chromatography. In this article, we will consider all the steps that contribute to overall analysis time and what measures may be taken to reduce their contribution and provide a holistic approach to improving sample throughput. Figure 1: Steps involved in an automated GC analysis. Non-productive time GC Equilibration Leak test Flame out test Pre-run events Chromatography Cool-down Ready Inject Autosampler Solvent wash Sample wash Sample pump Solvent wash Chromatography 15 http://www.thecolumn.eu.com

Table of Contents for the Digital Edition of The Column - March 2008

The Column - March 2008
Contents
News
Zosimus - Never Mind the Selectivity - Look at the Plate Count!
HPLC Analysis of Lysozyme in Different Types of Wine
Market Trends & Analysis
A Holistic Approach to Increasing Analytical Throughput on a Modern Gas Chromatograph
If It's Broke, Fix It - Q&A
The Applications Book
LC World Talk - Shimadzu's Newsletter for the HPLC Global Community
LC World Talk Contents
Applications of Ultra Fast HPLC
The World's Most Advanced Liquid Chromatograph
2D-HPLC for Bioanalysis "Co-Sense for BA" System
Metabolite Identification Software

The Column - March 2008