I don't know where to buy naphtha, so i use petrol instead. But there is no DMT product, so is the petrol's problem?
the problem is probably the pH. Octane, the primary constituent of gasoline/petrol is non polar, so the DMT has to be in it's freebase form to be soluble, meaning the solution has to be alkaline furthermore, commercially available gasoline/petrol has a buttload of additives which you may not wish to consume. A significantly safer alternative for your non polar solvent would be d-limonene, a.k.a orange oil. Significantly less flammable, at worst a mild skin irritant, no other known risks, and superbly cheap as it is a byproduct of orange juice manufacture.
AFAIK every solvent will extract a different spectrum of alkaloids. naptha happens to be one solvent that is very selective for n,n-dmt. basically solvents which consist of mostly aliphatic hydrocarbons (naptha, heptane, hexane, etc) will be more selective than aromatics like toluene, xylene, benzene etc. Aromatics will pull more additional alkaloids besides dmt and can be used to make jungle spice. Gasoline contains a proportionally high amount of aromatics, so using gas as a solvent would most likely behave more similarly to other aromatic solvents such as toluene or benzene. edit: I can confirm that using gas as a solvent does work for pulling dmt. The failure of the procedure was most likely the result of errors in previous steps of the process such as low pH.