About high rich water solution analysis by capillary column

[qazaqaz]

1) I have an Alltech EC Wax capillary column 30mX0.53mm (max temp 260). I would know can I use it for analyst oxygenate compound in 90%wt water (I don't want to detect water but water is solvent and GC is online next to reactor)? My trouble is much volume of water.
2) My teacher tell me column will collapse if a much water is feed to GC column. This is true or not?
3) My teacher recommend carbowax packed column because it bear with water than capillary one. This is right or not?

-Thank you so much for everry knowledge-
^___^

[chromatographer1]

Water more easily damages a capillary column than a packed column.

The water causes more damage if it is allowed to condense as a liquid with the column instead of completely being vaporized.

The packed column can tolerate a larger amount of water than can a capillary column.

Your teacher is correct. The only semi-exception is if the capillary is a PLOT column with porous polymer beads as the layer. But even then, the glue holding the beads can be damaged and reactive sites can be created. A packed porous polymer bead column is better and can tolerate a larger injection of water.

best wishes,

Rod

[AICMM]

qazaqaz,

Possible to do you compound list by headspace or spray and trap? Do you have access to a 6 port injection valve that you can use?

Best regards.

[qazaqaz]

If I use complete water vaporised condition, I can use my capilary column or not ?

[chromatographer1]

IF you can vaporize the water before injection and inject it as a gas so it will not condense in the column head then you will minimize the damage to your column.

But I did not say you can do that without damage to the column.

Is that your concern?

Columns are not meant to last forever. Work has to get done. But it costs money, how fast do you want to spend it?

It is not a question of CAN I do this, but SHOULD I do this.

Only you can answer that question.

If this is an academic exercise, then I would say NO, don't do it. If you need an answer and the analysis is the goal, then do what you have to do.

But what is wrong in using a packed column? They are cheaper and last a lot longer with abuse.

best wishes,

Rod

[Victor]

Rod has given you some very good advice.

I managed to use a 0.53mm ID DB-wax column with a 1.0 um film using 0.5 ul on-column injection atarting at 85 deg and programming to 180 deg. So presumably the water actually condensed on the front of the column, which as Rod says, is not a good idea. The samples I was using were quite clean and just contained free fatty acids, but I put down several hundred injections without noticeable column deterioration. I think a thicker film column is likely to be more robust. Note also this is NOT the same column as you are using-maybe your column will NOT last so long!

You need to decide how upset you or your teacher will be when your column fails. If you can afford to buy a replacement, then it might be worth considering. I would still use a packed column, but maybe your GC is not adaptable for use with such a column.