Question

Gas Chromatography- Mass Spectrometry

If the chromatographic elution peaks in the sample are far apart and analysis takes a relatively lon time, should you increase or decrease the column temperature program to improve analysis time? Explain your reasoning.

Answer 1

In GC, column temperature is one of the influencing factors in separation of components. There are two ways to set the oven column up: isothermal programming and gradient programming.

In the first case, temperature is held constant during the whole run. I think this is your case, since analysis took a long time and elution peaks are far apart. Now, I would improve the experiment making a temperature gradient program: here, you start the analysis at a low temperature to resolve the low boiling components and then increase it during the separation to resolve the less volatile analytes within the sample.

Now, it depends on what analytes you are trying to separate whether you increase column temperature continuously (for instance, 10 K/min) or you configure laps as separation time goes on. But definetely INCREASE the column temperature if your time is long and the peaks are far from each other.