Profiling of regioisomeric triacylglycerols in pistachio nuts by high-performance liquid chromatography-electrospray ionization mass spectrometry

In this contribution, a non-aqueous reversed-phase liquid chromatographic method coupled to electrospray ionization (ESI) tandem mass spectrometry (LC-MS) is used for the identification of triacylglycerol (TAG) down to the regioisomersic level in pistachio lipids. Furthermore, for effective profiling of TAG, a two-dimensional (2D) map was employed to identify the entire homologous series of TAGs especially, odd-numbered fatty acid and long-chain derivatives. Notably, TAGs were observed as pairs of regioisomers with distinct retention times and tandem mass spectra. Furthermore, more than 100 TAGs containing 26 fatty acids with 51-63 carbon atoms and 0-3 double bonds were identified in different pistachio samples. The developed method is effective and facile for the fast quantification of complex TAGs in pistachio samples at high selectivity.

Automated summary

A non-aqueous reversed-phase liquid chromatographic method coupled to electrospray ionization tandem mass spectrometry was used to identify triacylglycerols (TAGs) in pistachio lipids at the regioisomeric level. A two-dimensional (2D) map was employed for effective profiling of TAGs, specifically odd-numbered fatty acids and long-chain derivatives. TAGs were observed as pairs of regioisomers with distinct retention times and tandem mass spectra. Over 100 TAGs containing 26 fatty acids with 51-63 carbon atoms and 0-3 double bonds were identified in different pistachio samples. This method provides a fast and selective approach for quantifying complex TAGs in pistachio samples.