ToF-SIMS analysis of bio-systems: Are polyatomic primary ions the solution?

Molecular depth profiling of polymers with very low energy ions

“…Organic depth profiling with time-of-flight secondary ion mass spectrometry (ToF-SIMS) has become a major challenge, especially with the use of cluster ion beams which prove successful for depth profiling a variety of polymers [1][2][3][4][5][6]. In a recent paper [7], we have shown that a 75 nm polycarbonate (PC) layer could be depth profiled by using 200 eV Cs ions as sputtering beam: the most specific PC fragments signals were surprisingly stable all over the profile.…”

C60, Buckminsterfullerene: its impact on biological ToF‐SIMS analysis

“…There is an increase in intensity of the molecular ion signal from the drug, which then remains stable following ion doses well in excess of the traditional static limit 28 ( Fig. 1).…”

Surface Analysis of Organic Materials with Polyatomic Primary Ion Sources

“…This result was attributed to matrix effects, whereby ionization of the drug molecule was improved by the presence of the cholesterol (see Chapter 8 for more details). 141,142 Cholesterol can act as a source of protons, as it tends to form deprotonated molecular ions, [M − H] + . Similarly, phosphatidylcholine removes a proton from the environment by forming protonated molecular ions, [M + H] + , and therefore suppresses the formation of the protonated molecular ion in the drug.…”

“…Similarly, phosphatidylcholine removes a proton from the environment by forming protonated molecular ions, [M + H] + , and therefore suppresses the formation of the protonated molecular ion in the drug. 141,142 Therefore, the imaged drug distribution was the opposite of the real distribution, due to matrix effects.…”