Prospective Student

[nishasks]

Hi. I want to analyse ethanol water mixture by GC. wht type of column i will have to take. I tried BPX50 and Porapak Q.
Plz suggest........................

Regards
Nisha

[chromatographer1]

You should have no problem with the Q packed column.

For better peak shape of the water, use an R packed column. Use glass not steel tubing.

You also might use a Wax packed or capillary column.

best wishes,

Rod

[AUlee]

Thank you so much Rod,

I have the same questions on assay ethanol in water. I'm wondering is water detrimental to GC column VF-4MS CP8944? I have searched a lot online and I haven't found any reference give a clear explanation. So, would you please, or anybody else, be able to simply summarize what kinds of column is adaptable for the water in injection solvent, and what are detrimental?

I think that will be much valuable for new GC users to refer. Thank you

Lee

[chromatographer1]

When liquid water is found on the surface of a methyl silicone phase and fused silica tubing, damage will occur.

When water is in a vapor state little damage occurs, but of course, water does become liquid briefly as it partitions along the column, so a small damage will occur, usually not noticeable for weeks or months.

Water can also damage the PEG phases through their attachments to the fused silica surface, causing bleed to grow with time, and active sites to increase in number, losing inertness of the column.

Water does not harm polymer bead packings but may damage the glues attaching them to capillary walls. Packed columns are no problem as expected.

Keep H2O, HF, HCl, H2SO4, NH4OH, and other strong agents away from GC columns if at all possible.

Happy New Year.

Rod

[AUlee]

Thank you soooo much, Rod. Your reply is wonderful for me!
And happy new year!

Lee