# What would you recommend to isolate these compounds from cooking oil?

Recycled cooking oil, aka "gutter oil", is a major problem in countries such as China. I am doing some research to see if there's a reliable and quick way to determine if something is gutter oil.

I came across a Chinese paper that uses Solid Phase Micro Extraction with Gas Chromatography/Mass Spectroscopy. In this paper, they listed out a list of chemicals that are commonly found in their samples of gutter oil.

Originally, I was planning to use Surface Enhanced Raman Spectroscopy for detecting these chemicals inside a matrix but it seems like the fluorescence of the oil is masking the raman signals of these chemicals.

All of these chemicals are dissolved in the sample oil in trace quantities. The are (listed in order of priority):

Methyl-3-butenenitrile
Hexane
5-Cyano-1-Pentene
1- decyne
Cyclohexane
Allyl cyanide
Acetic acid
benzene
Methyl cyclopentane
3-butenyl isothiocyanate
Allyl isothiocyanate
N-heptane
Toluene
1-hexanol
Xylene
Heptanone


Are there any simple extraction/filtration techniques that could isolate some of the above for the purpose of Surface Enhanced Raman Spectroscopy? I am looking for a sample preparation method that is less involved as solid phase extraction.

• I have to admit I had never heard of 'gutter oil' - sounds nasty! However the description of your problem sounds very much like it is a textbook candidate for NMR fingerprinting and multivariate analysis. Almost no sample preparation is needed. A quick search shows that it is a method already being developed. – long Jan 5 '16 at 23:49
• I would suggest high performance liquid chromatography for such a medley of chemicals followed by $\ce{^{13}C}$-NMR. – A.K. Jan 6 '16 at 3:55