On-line reaction monitoring and mechanistic studies by mass spectrometry: Negishi cross-coupling, hydrogenolysis, and reductive amination.

Reaction monitoring using inductive ESI mass spectrometry allows chemical reactions to be tracked in real time, including air- and moisture-sensitive as well as heterogeneous reactions. Highly concentrated solutions can also be monitored for long periods without emitter clogging. Sheath gas assists in nebulization and a sample splitter reduces the delay time and minimizes contamination of the instrument.

Enhanced detection of olefins using ambient ionization mass spectrometry: Ag+ adducts of biologically relevant alkenes.

Spray solvent doped with silver ions increases the ease of olefin detection by desorption electrospray ionization (DESI). Characteristic silver adducts were generated in up to 50 times greater abundance when compared to conventional DESI spray solvents for the biologically significant olefin, arachidonic acid, in the positive ion mode. In the analysis of 26 lipids, silver adduct formation was highly favorable for fatty acids, fatty acid esters and prostaglandins but not applicable to some other classes (e.

Trace detection of non-uniformly distributed analytes on surfaces using mass transfer and large-area desorption electrospray ionization (DESI) mass spectrometry.

Ambient ionization methods such as desorption electrospray ionization (DESI) allow the analysis of chemicals adsorbed at surfaces without the need for sample (or surface) pretreatment. A limitation of current implementations of these ionization sources is the small size of the area that can be sampled. This makes examination of surfaces of large areas time-consuming because of the need to raster across the surface.

Hand-held mass spectrometer for environmentally relevant analytes using a variety of sampling and ionization methods.

A recently developed hand-held, rectilinear ion trap mass spectrometer, capable of performing in situ analysis, has been evaluated for a variety of environmentally relevant analytes. Different sampling and ionization methods were implemented, demonstrating the considerable versatility of this instrument. A discontinuous (viz.

Rapid hydrocarbon analysis using a miniature rectilinear ion trap mass spectrometer.

A miniature ion trap mass analyzer was applied to the analysis of traces of hydrocarbons and simple heteroatomics in the vapor phase and in aqueous solution. Vapors of acetone, acetic acid, acetonitrile, benzene, butanethiol, carbon disulfide, hexane, dichloromethane, naphthalene, toluene and xylenes were detected and quantified using solid sorbent trapping and, in some cases, by passage through a membrane interface. Aqueous solutions of benzene, toluene, xylenes, hexane and a petroleum naphtha distillate were examined using the membrane interface.

Alkali metal-cationized serine clusters studied by sonic spray ionization tandem mass spectrometry.

Serine solutions containing salts of alkali metals yield magic number clusters of the type (Ser(4)+C)(+), (Ser(8)+C)(+), (Ser(12)+C)(+), and (Ser(17)+2C)(+2) (where C = Li(+), Na(+), K(+), Rb(+), or Cs(+)), in relative abundances which are strongly dependent on the cation size. Strong selectivity for homochirality is involved in the formation of serine tetramers cationized by K(+), Rb(+), and Cs(+). This is also the case for the octamers cationized by the smaller alkalis but there is a strong preference for heterochirality in the octamers cationized by the larger alkali cations.