Petroleum compounds residues in food samples

[UMAchem]

Hi to all!
I have a food sample how smell like kerozene, and i need to know a analytical method by GC MS or FID, to detect that tipe of compounds!

Thanks in advance for your help!

[chromatographer1]

One can use headspace or extraction.

Methylene chloride extraction followed by concentration and an internal std of some unlikely component would be the best path.

You need to be able to measure small amounts accurately.

A simple methylene silicone 0.53mm capillary would be a suitable choice. Use a large volume injection technique if possible.

You might get some ideas from pesticide analysis methods.

Good luck.

Rod

[UMAchem]

Thanks Rod for the information, but maybe will be better if some one can showme a method to do that job with the GC MS.

Thanks again for all your help!

[chromatographer1]

I once had to perform analysis for residual oil (C17-C37) in 250 ppb in a soap.

Wasn't fun but I had to preconcentrate and use large volume injection to quanitate accurately.

Kerosene is much lower carbon number but concentration may be required.

Review EPA methods for a suitable procedure.

Good luck,

Rod

[Peter Apps]

Off-odours that smell like kerosene can come from a variety of compounds that do not themselves occur in kerosene. Commonly, kerosene off-odour in food comes from pentadiene, which is produced by mould.

Start with an equilibrium headspace analysis. If the food is in a reasonably air tight package you can take a sample of the package headspace, if not put some of the sample into a septum-capped vial and warm it to 40 - 50 degrees C. Take about a 100 microliter sample with a warmed gas-tight syringe, and inject with a split ratio of about 5:1. The solvent delay on the MS must be 0 (the MS must acquire data from the beginning of the GC run). If you can, use a thick film column and start the column temperature programme at 30 degrees C or below, programmed at about 5 degrees per minute.

[UMAchem]

Thanks for your help, i will take a try!

[UMAchem]

Hi Peter, can you please tell me which fragments can i seek in the GC MS!

Thanks in advance for your help!