I am looking for a sample preparation technique for total petroleum hydrocarbons that can separate the aliphatic and the aromatic components for GC analysis.
This is very routine in most of the petrochemicals refinery. The technique is called fractional absorption based on evaporation temperature of the compounds under investigation. If the difference is very small then carry out the evaporation under vacuum and low temperature (which is the procedure you have to standardize / optimize).
You can find an extraction procedure of SPE at US EPA 550.1 for polycyclic aromatic hydrocarbons. Find the attached file.
Based on the group reactions of organic analytical chemistry, you can react the aliphatic or aromatic hydrocarbons with other chemical reagents, and increase or lower their selective adsorption abilities.
You could use silica as adsorbent, in a column or cartridge, hexane and dichloromethane as solvent to elute the aliphatic and aromatic compounds respectively.
For example, you should revise the attached publication.
Article An analytical method for quantifying petroleum hydrocarbon f...
You can check my methodology for isolation of C6-C20 hydrocarbons by SPME coupled with GC-FID. I think, it may interest you.
Article Application and optimization of headspace solid-phase microe...
through the liquid chromatography column preparative with silica and alumina, unep method
Silica gel is not efficient; you have to be very careful and have excellent technique. I don't recommend it.
Use silver-impregnated alumina; you will retain the aromatics quite efficiently. You'll physically see them band - it's yellow. You'll catch everything from naphthalene on up; you'll get some of the monoaromatics but the retention is typically less than 70% efficient for benzene.
You can also use DMSO or DMF to partition aromatic/aliphatic hydrocarbons. More costly than the alumina and more of a pain.
I agree with Pedro José Sanches Filho. You can successfully separate aliphatic from aromatic hydrocarbons using a simple column chromatography. The aliphatic hydrocarbons will elude first before the colored aromatic hydrocarbons.
I am searching articles speaking about solid phase extraction application in petrochemical analysis..is there someone that could help me?
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