The valuable role of high-performance thin-layer chromatography in the lipidomic analysis of Thlaspi arvense, an emerging feedstock for biofuel production

Abstract Two different lipidomic approaches, high-performance thin-layer chromatography coupled to electrospray ionization‒mass spectrometry (HPTLC‒ESI‒MS) and liquid chromatography coupled to electrospray ionization‒mass spectrometry (LC‒ESI‒MS) were used for the quantitative analysis of lipid fractions obtained from different seed maturation stages from pennycress ( Thlaspi arvense ), an emerging feedstock for biofuel production. Pennycress seed oil is characterized by its unusually high content in erucic acid (C22:1), mostly accumulated in the form of triacylglycerols (TAG). Their performances were compared under optimal conditions for each, and the coherence of results obtained from both techniques were evaluated. The acquisition of HPTLC‒ESI(+)‒MS spectra obtained at the same time of ionization for each of the seed maturation stages in a rapid and simple way, revealed two important types of information: first, the normalized profiles of TAG ion abundance, without any calibration step. These results and the results from LC‒MS were in agreement concerning erucic acid incorporation and were statistically correlated. Results from both techniques confirm the incorporation of 22:1 into TAG already at the initial stage of seed maturation (TAG 58:5), as well as the increase of 22:1 and 20:1 as maturation progresses (TAG 60:4 and TAG 62:4, which correspond to 20:1/18:2/22:1 and 22:1/18:2/22:1, respectively). Second, it revealed the sn -positional analysis by HPTLC‒ESI(+)‒MS/MS of several relevant TAG species in pennycress seed maturation. This analysis indicated that linoleic acid was esterified at sn -2 in all stages of seed maturation of several quantitatively important TAG subclasses and, therefore, suggesting a high specificity of lysophosphatidic acid acyl transferase ( LPAT ) for linoleic acid even in a high-erucic-containing species such as pennycress. All of these results support the utilization of HPTLC as a rapid and reliable methodology, compatible with LC‒MS, for the analysis of complex lipid mixtures such as those found in plant seed oils.