Injecting small amounts of water (solvent) into a non-polar capillary column will not damage the phase; however, this may not be the case for mid and high-polarity columns.
Several precautions should be taken when water is used as a solvent:
- The water is completely vaporized before it enters the column and the water does not re-condense inside the capillary column. If GC oven temperatures are cool enough to allow the water vapor to condense:
- Use a Polar-Deactivated guard column. This will allow the water to be completely vaporized before it reaches the column.
- Do not use cold or heated on-column injection modes. Use only injection modes that vaporize the solvent before it enters the column: split, splitless, or direct injections.
- The injection volume should be small: 1µL or less. Larger volumes will create a backflash, where the expansion volume of the solvent will exceed the volume of the injection port liner. This can lead to poor reproducibility and/or “ghost” peaks.
Additional information can be found in our Capillary Column Installation Guide.
