Sample Preparation for MALDI-MS

In its current state, MALDI is primarily based on the laser desorption of solid matrix-analyte deposits. The technique suffers from some disadvantages such as low shot-to-shot reproducibility, short sample life time and strong dependence on the sample preparation method, figure 2. A few research groups have investigated the use of liquid matrices, to increase sample lifetime and eliminate the search for sweet-spots, by exploiting the self-healing properties of the sampling position through molecular diffusion. Table 1 shows different sample preparation methods.

Table 1: Different sample preparation methods

Solid Matrix
Liquid Matrix
Special preparations
Dried-droplet
Chemical liquid
Solid supports
Vacuum-drying
Particle-doped (two-phase) liquid
MALDI on 2D-gels
Crushed-crystal
Chemical-doped liquid
Insoluble samples
Fast-evaporation
-
-
Overlayer
.
-
Sandwich
-
-
Spin-coating
.
-
Slow-crystallization
-
-
Electrospray
.
-
Quick and dirty
-
-
Matrix precoated targets
.
-