It is accepted that normalizaWon with the aid of different methods should give more or less the same ion maps leading to, at least, similar conclusions. Comparing images obtained with TIC, median and RMC normalizaWon we may observe that in the case of betaine aldehyde derivaWzaWon, the image is almost the same, whereas with NDEC matrix the image with RMS is substanWally different (see figure ).