Quantifying Capsaicinoids from Chili Pepper and Motor Oil Mixtures Used in Elephant Deterrent Fences

Human–elephant conflicts continue to escalate as African elephants ( Loxodonta africana ) attempt to forage on cultivated crops. Chili pepper fencing is used as a deterrent but has varying success rates. These fences are constructed with crushed chili peppers, typically mixed in motor oil, placed on cloths, and strung around crop fields. This mixture is made using different formulas involving oil and sometimes water, but each takes advantage of the “heat” and discomfort produced from capsaicinoids, the active ingredients in chili peppers. Using LC–MS technology, we examined some of these formulas and preparation methods. The development of this methodology is to our knowledge the first time this type of analysis has been conducted with chili and motor oil mixtures. By examining the differences in Scoville Heat Units (SHU), we confirmed that mixing with oil played an important role and that the SHU was no different by boiling crushed chilis in water before combining with oil compared to directly combining the crushed peppers with oil. Allowing the crushed peppers to remain in the mixture rather than filtering before mixing showed only a slight benefit. This LC–MS methodology provides a new tool for conservationists to compare the efficacy of chili fence formulas, which may allow for improvement of this deterrent method via further field testing.