Identification of Unsaturated Fatty Acid Amides Involved in Talc by FABMS/MS Measurements

Abstract

Unsaturated fatty acid amides were separated from the organic compounds contained in both Australian and Korean (Democratic People's Republic of Korea) talcs. From the equal retention times in GC and HPLC analyses, these were considered as an identical compound. The molecular formula (C₁₈H₃₅N₁O₁) was determined from ¹H-NMR and high resolution EIMS spectral data, while the double bond position of this amide was successfully determined by charge remote fragmentation of the FABMS/MS (CAD) spectra for the precursor ion (M + Li)⁺. The amide compound was identified to be oleamide [CH₃(CH₂)₇CH=CH(CH₂)₇CONH₂]. Since Chinese (Peoples Republic of China) talc contains erucamide [CH₃(CH₂)₇CH=CH(CH₂)₁₁ CONH₂] as reported previously, the unsaturated fatty acid amide involved in Australian or Korean talc is characteristically different from the one in Chinese talc by the -(CH₂)₄-alkyl chain length.