Chromatography Forum

I know its not the best thing for column longevity but how much damage an I likely to cause to a HP35 column if I inject samples in a water matrix directly onto it? Is there any thing I can do to prevent problems? Would a pre-column do any good?

I know its not the best thing for column longevity but how much damage an I likely to cause to a HP35 column if I inject samples in a water matrix directly onto it?

It largely depends on starting temperature of the oven.
If water won't condense in the column it practically won't harm.

If shooting water, cool down the injection port to just over 100. Maybe 125 or so, otherwise you run the risk of greatly exceeding the volume of your liner.

If shooting water, cool down the injection port to just over 100. Maybe 125 or so, otherwise you run the risk of greatly exceeding the volume of your liner.

Yep, and keep injection volume as low as possible. However it has nothing to do with column lifetime.

Most siloxanes can handle water, but be careful. The higher the polarity, the more sensitive phases get for hydrolization. There are backbone stabilized phases out there that have even bettre tolerance (35 Sil MS).

For any phase, water is a problem if it gets in the column when it is HOT. (like via the carrier gas or a leaking fitting/septum).

Water as matrix is usually not a problem as the water peak elutes at low oven temperature. Be aware that injection and detection part however, can develop activity, depending on temperature used.
Water evaporation is a bigger issue because of expansion volume. Use 4-5mm ID liners. Be careful with wool. We generally recommend the cyclosplitter or the double gooseneck for inejcting water samples

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