Dependency of signal-to-noise ratio for peptide protonated ions on laser intensity in MS detection with CHCA matrix (black, curve 1 and 2), with 8 layers of silicate fabricated with water washing between deposition of each polyelectrolytes (red, curve 3 and 4), and with 8 layers of silicate fabricated without water washing (blue, curve 5 and 6). Silicate films were coated with OTS after calcination. The sample was a mixture of [Sar1, Thr8]-angiotensin II (squares) and neurotensin (triangles), 1 pmol each. Error bars are omitted for simplicity.