Best analysis for alcohols in water

[Nikko]

I would appreciate any advice on monitoring low molecular weight alcohols in water using headspace analysis. We currently have a 7890 GC with a 5975C MS. I have found methods that look at halogenated compounds and aromatics in water but not concerning alcohols. The methods use a DB624 column. The samples are salted and use short incubation times, about 10 min. Any suggestions on types of columns or sample prep would be appreciated.

[krickos]

Hi

Well your stated approach seems fine in general.

Is your "matrix" repateble? Salting out (ie adding like 0,5g sodiumsulphate to all vials) typically is good for water samples and may fine with the extarnal calibration technique. But if you may run into organics in matrix standard addition is generally a better approach.

The column should work for your purpose, agilent has a retention time index for that column in their catalouege.

To answer more in detail could you please state what typical alcohols you want to monitor and at what concentrations?
Alcohols in water generally in a sensitivity way is very dependend on HS oven temperature, sample volume and equilibration time.

10-15 mins of equilibration time may work but generally requires 1ml sample in 10ml vial or max 2 ml sample in 20ml vial to get a fairly stable equilibrum and a suiteble headspace oven temp.
Also in water one should stay below the boiling point of the lowest boiling alcohol with regard to headspace oven.
If you look for traces you generally need to increase sample volume and increase vial equilibration time.