Fig. 2.

Weighted regression for intercomparison assessment of 13 selected metabolites from in-house yeast-based reference material measured with both HILIC-HRMS and GC–MS/MS methods in positive ionization mode. External calibration with internal standardization (fully ¹³C-labeled internal standard) was performed for each concentration (nmol vial⁻¹). Reciprocal of the squared predicted values for standard deviation was used for weighting factors. The inset images showed the zoom-in regions of interest for clarity