| Surface activity effects in fast atom bombardment (FAB) and liquid secondary ion mass spectrometry (LSIMS) were investigated using two quatemary ammonium cations. It was shown that the intensity of tetradecyltrimethylammonium (TTA{dollar}sp+),{dollar} a surface active cation, was initially strong and then decreased over the lifetime of the sample. The FAB signal from tetraethylammonium (TEA{dollar}sp+),{dollar} a non-surface active quaternary ammonium cation, was shown to be initially weak followed by a short lived burst of high intensity prior to the end of the experiment. Secondary ion imaging revealed that TTA{dollar}sp+{dollar} yielded relatively uniform signal intensity from across the entire surface of the sample, while TEA{dollar}sp+{dollar} yielded non-uniform secondary ion emission across the surface of the sample. The explanation of the non-uniform TEA{dollar}sp+{dollar} emission was based on a Marangoni force.; A new micro-electrospray (ES) source was developed and tested using continuous infusion and capillary electrophoresis to deliver solution to the emitter. A mechanically shaped conical tip was chemically treated with a mercaptan reagent to improve the adhesion of a vapor deposited gold layer. These capillaries were shown to operate in excess of 100 hours, spray a variety of solutions, and provide a mass spectrometric limit of detection of 7 attomoles for cytochrome C from an aqueous solution.; EH MS was used to probe the preferential solvation of the proton in a mixed solvent system containing 95/5 (v/v) water/glycerol. In a 95/5 (v/v) water/glycerol solution containing 40 mM HCl, the most intense peaks in the spectrum are the protonated glycerol dimer ((G{dollar}rmsb2+Hrbracksp+){dollar} and trimer ((G{dollar}rmsb3+Hrbracksp+).{dollar} This indicates preferential solvation of the proton by glycerol, and is in good agreement with known gas and solution phase chemistry of the two solvents. The relative abundance of water clusters differed markedly from that reported in the literature for the gas-phase hydration of the proton; it was therefore inferred that the distribution may reflect solution phase rather than gas phase chemistry. |
