A MALDI sample plate 1 is disclosed which comprises a metallic substrate
2 having a circular groove or moat 3. A hydrophobic polytetrafluoroethylene
layer 4 is applied to the substrate 2 and a central portion 5
of the substrate 2 is laser etched which roughens the surface of the
substrate 2. A thin polystyrene layer is then applied to the polytetrafluoroethylene
layer 4 and the central portion 5.