Ultra-high performance supercritical fluid chromatography coupled with quadrupole-time-of-flight mass spectrometry as...

Secondary metabolites are an almost unlimited reservoir of potential bioactive compounds. In view of the wide chemical space covered by natural compounds, their comprehensive analysis requires multiple cutting-edge approaches. This study evaluates the applicability of ultra-high performance supercritical fluid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPSFC-QqToF-MS) as an analytical strategy for plant metabolites profiling. Versatility of this analytical platform was first assessed using 120 highly diverse natural compounds (according to lipophilicity, hydrogen bond capability, acid-base properties, molecular mass and chemical structure) that were screened on a set of 15 rationally chosen stationary phase chemistries. UHPSFC-QqToF-MS provides a suitable analytical solution for 88% of the tested compounds. Three stationary phases (Diol, not endcapped C18 and 2-EP) were highlighted as particularly polyvalent, since they allow suitable elution of 101 out of 120 natural compounds. The systematic evaluation of retention and selectivity of natural compounds further underlined the suitability of these three columns for the separation of natural compounds. This reduced set of key stationary phases constitutes a basis for untargeted scouting analysis and method development. Even if they were less versatile, stationary phases such as endcapped T3C18, polar P-PFP, were nevertheless found to provide extended selectivity for specific natural molecules sub-classes. Finally, the identified polyvalent conditions were successfully applied for the analysis of complex polar and non-polar plant extracts. These first experimental hits demonstrate the full applicability and potential of UHPSFC-QqToF-MS for plant metabolite profiling.