By angela on Thursday, May 8, 2003 - 04:32 am:
Can anybody please tell me in details what bleeding of a coloumb is?and what causes it!
By DaT on Thursday, May 8, 2003 - 06:20 am:
Bleeding of a column is the (very slow) degradation of your column itself, which you measure.
Your stationary phase will slowly deteriorate, and this causes a bit of elevation in your chromatogram. At higher temperatures, this effect will be bigger.
With an FID you can get a "good" view of the columnbleed by injecting a blank water.
Of course this depends on your temperature program.
If you use a Temperature program with a steady temp (lets say 30 min at 70°C) you will see a straight line and you won't notice the bleed.
If you use a rise in temperature (example start at 70°C and then go to 320°C with 15°C/min) you will see your baseline rise when you reach +- 250 °C due to the stationary phase deteriorating a bit faster.
By angela on Monday, May 12, 2003 - 05:15 am:
thank you!
By PPG on Friday, May 23, 2003 - 08:47 am:
You can notice that polar phasis, has more bleeding than apolar ones, which are chemicaly stronger and has a longer life