Wash a sample of the oil with some vinegar, then check the vinegar for harmala-style fluorescence under UV light. The oil itself may display fluorescence, but there are plenty of other fat -soluble compounds that also fluoresce, along with certain polyunsaturated fats/PUFA.

I've noticed that harmalas may display exceedingly weak solubility in medium naphtha, but this may have been down to stearic acid contamination, soooo… you might see a tiny solubility of the harmala alks in the seed oil, if they've formed salts with longer-chain fatty acids, which would essentially be harmala soaps. In that sense, take care to minimise emulsions when washing with vinegar.