Fig. 1From: MIDcor, an R-program for deciphering mass interferences in mass spectra of metabolites enriched in stable isotopesNatural MID, measured for cold TMS-derivative of aspartate. The raw data for two independent samples shown in Table 1 were corrected for the mass shift and normalized (Eqs 1–3). The calculations were performed as described in Additional file 1 Text S1Back to article page