Determination of toxic phorbol esters in biofertilizer produced with Jatropha curcas seed cake

Seeds of Jatropha curcas contain oils, essential amino acids, and toxic phorbols that are found to be carcinogenic. Application of J. curcas seed cake for producing biofertilizer for growing sweet potato was studied in this work. The J. curcas seed cake, soil, and sweet potato were examined to determine the contamination of phorbol esters residue after the plant was treated with J. curcas seed cake fertilizer. Our study develops a technique to confirm the presence of phorbol esters residue by using liquid chromatography-tandem mass spectrometry with multiple reaction monitoring mode that detects the ionization of parent molecule with mass 711 to precursor and product ion with mass 311 and 293, respectively. This technique is recommended to confirm phorbol esters residue. The results showed that both sweet potato and soil after harvesting did not have contamination with toxic phorbol esters.