Electrospray ionization has recently emerged as a powerful technique for producing intact ions in vacuo from large and complex species in solution. To an extent greater than has previously been possible with the more familiar "soft" ionization methods, this technique makes the power and elegance of mass spectrometric analysis applicable to the large and fragile polar molecules that play such vital roles in biological systems. The distinguishing features of electrospray spectra for large molecules are coherent sequences of peaks whose component ions are multiply charged, the ions of each peak differing by one charge from those of adjacent neighbors in the sequence. Spectra have been obtained for biopolymers including oligonucleotides and proteins, the latter having molecular weights up to 130,000, with as yet no evidence of an upper limit.

https://science.sciencemag.org/content/sci/246/4926/64.full.pdf

Electrospray ionization for mass spectrometry of large biomolecules

A review on the utilization of fly ash

Advanced polyimide materials: Syntheses, physical properties and applications

Chemistry has its origins as a quantitative science in the careful weighing of products and reactants by Lavoisier and his followers beginning some 200 years ago. Ever since then, the constantly evolving gravimetric balance has been a faithful servant of the laboratory chemist and has played a major role in developing the analytical methods that are the foundation of contemporary chemical science. Perhaps the ultimate stage in the evolution of that balance is represented by the modern mass spectrometer. It is able to determine with high precision the masses of individual atoms and molecules by transforming them into ions and measuring the response of their trajectories in vacuo to various combinations of electric and magnetic fields. Clearly, the sine qua non of such mass determination is the transformation of analyte atoms and molecules from their initial state in a sample to ions in vacuo ready for ”weighing.” Over the years, ingenious investigators have produced a variety of methods for achieving this transformation. One of them, electrospray ( E S ) ionization, has recently shown itself capable of producing intact ions, with multiple charges, from remarkably large, complex, and fragile parent species. Our assignment here is to review what has thus far been learned about this still uncommon technique and what it seems able to offer practitioners of mass spectrometric analysis. Our approach will be to set forth the present state of the ES ionization art in terms of a sort of menu of its procedures, processes, performance, and promise. Until very recently we have been almost the only group that has worked with ES ionization since the pioneering efforts of Malcolm Dole (1) some 20 years ago. Consequently, this review is more tutorial than most. Moreover, it may seem like a cook book that is overly preoccupied with the authors’ own culinary adventures. The reasoil is that many of the dishes to be described were first tried out in our own kitchen. Therefore, we earnestly urge the reader to remember what every gourmet knows: the piquancy of any dish on a bill of fare is due much less to its ingredients than to the skill of the chef whc. prepares it.

Electrospray ionization–principles and practice

L'effluent de chromatographie en phase liquide projete electrostatiquement dans un bain de gaz froid cree une dispersion de gouttelettes chargees qui s'evapore rapidement. Lorsque les gouttelettes deviennent plus petites, l'augmentation de la densite de charge superficielle et la baisse du rayon de courbure creent un champ suffisamment fort pour desorber les ions du solute. Une partie passe a travers un canal et forme un jet libre supersonique, puis passera dans l'analyseur de masse

Electrospray interface for liquid chromatographs and mass spectrometers.

Quantization of ion microprobe mass spectrometric analyses has been complicated by the variation in the ion yield of an element contained in different matrices. This work demonstrates that, for O− and Cs+ bombardment, these ion‐yield variations are solely attributable to variations in the matrix sputtering yield. It is argued that the matrix sputtering yield determines the near‐surface concentration of the ion‐yield‐enhancing species O and Cs.

Mechanism of the SIMS matrix effect

The use of a laser as a tool for annealing of ion‐implantation damage is described. The principal results obtained are as follows: (1) electrical measurements show that activity comparable to that of a 1000 °C 30‐min anneal can be obtained; (2) TEM measurements show that complete recrystallization of the damaged layer occurs during the laser anneal; (3) impurity profiles obtained from SIMS measurments show that the dopant atoms remain in the LSS profile during annealing. Simple diodes were fabricated to examine the feasibility of the method for device fabrication.

Physical and electrical properties of laser‐annealed ion‐implanted silicon

Electrohydrodynamic ionization mass spectrometry - the ionization of liquid glycerol and non-volatile organic solutes

Determination of the surface predominance of toxic elements in airborne particles by ion microprobe mass spectrometry and Auger electron spectrometry

The pure element secondary ion yields under oxygen and cesium ion bombardment are shown to be solely dependent on a) the ionization potential (or electron affinity for negative ionization) of the sputtered atom and b) the reciprocal of the matrix sputtering yield which determines the equilibrium concentration of implanted oxygen or cesium. This unified approach accounts for the yields of C±, Si±, Ge± and Sn± from the pure elements as well as of Ga± and As± from gallium arsenide.

Charles A. Evans

Papers

Mechanism of the SIMS matrix effect

Physical and electrical properties of laser‐annealed ion‐implanted silicon

Electrohydrodynamic ionization mass spectrometry - the ionization of liquid glycerol and non-volatile organic solutes

Determination of the surface predominance of toxic elements in airborne particles by ion microprobe mass spectrometry and Auger electron spectrometry

A unified explanation for secondary ion yields