On the distributions of ion/neutral molecule clusters in electrospray and laser spray—A cluster division model for the electrospray process

Abstract

The clustering of a medium-sized, involatile, neutral molecule, octyl ␤-D-glucopyranoside (OG), with Na ϩ , Ca 2ϩ , and Yb 3ϩ (M zϩ ) ions in electrospray (ESI) was investigated using laser spray (LSI). 3ϩ , where W represents the water content at the time of dissociation. Based on this study, a cluster division model for electrospray of aqueous solutions of strongly solvated ions is proposed: the Rayleigh droplet disintegration process, which is well-established for the initial stages of electrospray, maintains its general character as it proceeds through a final regime of multiply charged cluster dissociations to the singly and multiply charged ions in mass spectrometry. In the dissociation of multiply charged clusters, the size of each daughter cluster is roughly proportional to the square of the cluster charge. Observed cluster distributions are consistent with a mixture of symmetric and asymmetric cluster dissociations. (J Am Soc Mass Spectrom 2006, 17, 151-162)

Denaturation of α‐lactalbumin and ubiquitin studied by electrospray and laser spray

“…This indicates that the laser heating seems less effective than lowering the pH of aqueous solution for the denaturation of this protein under the present experimental conditions. In other words, laser spray enables observation of the intermediate transition states of proteins in an appropriate buffer 17–20…”

“…The general experimental procedures are similar to those described previously 17–20. In brief, a stainless steel capillary (i.d.…”

“…A comparative study for these two compounds was made using electrospray and laser spray. In laser spray developed in our laboratory,17–20 the tip of an electrospray capillary is irradiated with a continuous CO 2 laser beam (10.6 µm). In our previous work, applying a relatively low laser irradiation level (a laser power of ∼2 W and a focal spot size of ∼0.3 mm) resulted in a quiescent and smooth vaporization of aqueous solutions.…”

Stability analysis for double‐stranded DNA oligomers and their noncovalent complexes with drugs by laser spray

“…General experimental procedures were similar to those described previously 28–37. In brief, a stainless‐steel capillary (inner diameter 0.1 mm, outer diameter 0.2 mm) parallel to the interface plate was supplied with a sample solution by using a syringe pump (type 11 Plus, Harvard Apparatus, Holliston, MA, USA).…”

“…Laser spray, which was developed by Hiraoka et al ,28–37 is a promising tool for the characterization of biomolecules. It enables complete and prompt dissociation of the noncovalent bonds without any fragmentation of DNA moieties 34, 37.…”