[Kadvigus]

I am currently working on biofuels and my query is regarding its innate chemistry. The producer of the biofuel claims it to be straight chain paraffins. However, it was determined to contain iso-paraffins also,... resonable. When a bench test was carried out, the fuel was determined to contain negligible quantities of aromatics which, they said, was the result of isoparaffin's specific ion overlap.

My query is "What is specific ion overlap"? 

[Arkcon]

Can you tell us specifically what your analytical method is?

[Wastrel]

Filling in a lot of gaps with guesswork suggests that aromatics were expected on the basis of a mass spec and this was later put down to the tendency of the ions of  large branched alkanes to fragment.  If the interpretation is being done automatically then whatever fragmentation pattern those fragments overlap with produce a false result.  Think fourier analysis or orbital overlap.