Head sapce method development and validation

[prashant.pqa]

Dear All
I have develop one GC-MS method for one constitutent of oil. As this method i developed by using Standard. I tried diffrent solvent to extrat this constitutent from oil and injected to GC-MS system. But there is no any peak after extraction.
So i planning to do head space. But befor going to head space i want to know how i can validate the method by using head space.
The standard compound used is a soid and melting point is 65 °C.
Reference, sugestion will be appriciated.

[Peter Apps]

We need to know what kind of oil (e.g. petroleum, vegetable or essential etc) and what kind of compound.

Also I am not clear how you developed a method for a compound that you cannot extract from the sample. Do you perhaps mean that you found a set of GC conditions that work for standards ?

Peter

[chromatographer1]

Assuming your analyte compound has some volatility at temperatures above 65°C and assuming your matrix can melt at 65°C then it should be possible to get some equilibrium of the volatile analyte at some temperature above 65°C by static headspace.

I once showed that benzene 112-TCE and some other toxic residual solvents were not present in fatty acid salts as they melted at temperatures below 110°C. Using a solvent to spike weighed samples with the residual solvents of interest I was able to show by linear regression of the spiked samples that the solvents were not present.

Just make certain that the liquified sample and the spiked additions are in one liquid phase, the three or more spike levels are linear, and that the analysis is reproducible. You should not have any problems validating the method for the volatile compound you wish to measure to the satisfaction of the regulatory authorities.

best wishes,

Rod