Fig. 7 The ion map for m/z 734, m/z 766, m/z 798, and m/z 744 obtained from the slices of the spinal cord for the DAN matrix with the different number of matrix layers (A) and four different heights of spraying nozzle (B) for the positive ionization mode (matrix: 2.5 mg/ml DAN 50% ACN). Consider different ion maps for different spraying nozzle heights (Z) and the number of layers (L) in the case of m/z 798.