Tech Tip: Random loss in sensitivity of injected samples through a batch

Most problems that occur in Gas Chromatography either gradually increase in severity over time or suddenly become a large issue, preventing further analysis by the instrument.

Random problems occurring infrequently are often ignored for long periods of time as the sample is simply re-analysed and the results are correct the second time. The problem itself can be hard to track down to determine the cause and then to provide a fix, as it isn't a continuous problem.

HOW TO FIX THIS

Tech Tip: Splitless injections - how long until you open the split exit?

Splitless injections are used to transfer all of the injected analytes onto the analytical column for separation and detection and are therefore used for low concentration samples. Opening the split exit too early causes any remaining analytes in the inlet to be flushed out of the split exit and lost. Opening it too late (or not at all) leads to a long, tailing solvent peak which can interfere with the separation and detection of early eluting analytes and provides a higher baseline well into the chromatogram.

Tech Tip: The Power of Sample Introduction

Sample introduction or the GC inlet parameters are very often overlooked when developing a GC or GC-MS method, but these parameters are so powerful that they can result in success or total failure of an application and as a result are also the main area for troubleshooting and maintenance within the GC system.

 
The main techniques in sample introduction are:

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