Hydrostability GC FID

[SuperChemie]

I have an "injecting water onto the GCFID" question. We are taking our product and subjecting it to high amounts of water (50%-90%) to track the breakdown into its starting materials. I have read through other "water as solvent" posts on here and read about the volume expansion problem. Right now, the method we run to measure my analytes uses split 20:1. Is it not possible to measure my analytes by GCFID because of the water? Does anyone have an idea about the best way to go about this?

If I just dilute the sample in MeOH or ACN and then shoot it on, will that work or is that still going to be too much water? I have never used water as a solvent and I am just nervous about ruining something.

If anyone can help or point my in the right direction that would be great!

[Ron]

You should be fine. If you run a split and keep the oven starting temperature at 50C or higher there should be no issues with the water.

[Consumer Products Guy]

I agree, I think you're making too much about the water content. We assay alcohol products routinely on GC-FID capillaries, and they're all in water solutions and diluted with water. We inject 0.5ul.

[chromatographer1]

Water is usually harmless to most GC phases and tubing. The exception to this rule if IF the water is in a liquid state and not as a vapor.

Always try to keep water in a gaseous state within the column and you should not have any problems. But liquid water, especially on certain PEG phases, should be avoided.

Best wishes,

Rodney George
consultant

[SuperChemie]

Thank you for the responses.

I will inject some samples with varying concentrations of water to see what the peaks look like. I have set the injection volume to .2uL and the starting oven temp is 50C. I will post how it turns out.

[AICMM]

SuperChemie,

HP, Agilent or Varian GC? I will be curious to hear about your results.

Best regards.