Fig. 6 The relationship between the chosen peaks’ intensities and signal-to-noise ratio (s/n) in terms of the number of matrix layers (A) and the spraying nozzle height (B) for the positive ionization mode rat spinal cord tissue slices (matrix: 6 mg/ml norharmane (chloroform:MeOH:H2O))
The problem with that matrix lies in the fact that, for several m/z values, we obtained different ion maps in comparison with DHB matrix (see discussion chapter).
DAN (2.5 mg/ml 50% ACN – positive ionization mode)
For this matrix, the highest position of the nozzle (z=1) and 16 layers seem to be the best setting when the peaks intensities and the s/n ratios are considered (see: Fig. 8). But looking at different ion maps (see: Fig. 7), 14 matrix layers seem to give better results. For several ion maps, additional matrix layers blurred the picture. The same is observed for z=1 and z=5; thus, z=5 seems the best.