Mass Spectrometric Sampling of a Liquid Surface by Nanoliter Droplet Generation from Bursting Bubbles and Focused Acoustic Pulses: Application to Studies of Interfacial Chemistry

Abstract

Table of ContentsPreferential ionization of tetraethylammonium vs cesium S2 Rayleigh limit calculations S3Calculations of droplet residence time in the transfer capillary S3Calculation of droplet evaporation time S4

Zero volt paper spray ionization mass spectrometry for direct analysis of samples on filter paper substrate

“…One of the potential key parameters we suspect is the heat transfer inside the capillary as pointed out by Thomas et al . The velocity of air flow inside the capillary is estimated to be close to that of a sound (~245 m/s at 450 °C, Hagen‐Poiseuille's law) and it is temperature dependent (~531 m/s at 25 °C).…”

“…Understanding of ionization mechanisms is important to obtain the best available results for samples. As aforementioned, ionization mechanisms of SAII and zvPSI have been discussed previously . The main question is how charged droplets are created from initially neutral droplets without electric potential.…”

“…More recently, Thomas et al . have reported gas‐phase ion generation from near neutral droplets (<0.1% of the Rayleigh limit), which were produced by bubble bursting and focused acoustic pulses . As a mechanism of ion generation from relatively large (100–250 µm) initial droplets, which may have similarity to zvPSI, statistical fluctuations was proposed as the most likely cause of the initial charge separation.…”

“…More recently, Thomas et al have reported gas-phase ion generation from near neutral droplets (<0.1% of the Rayleigh limit), which were produced by bubble bursting and focused acoustic pulses. [34] As a mechanism of ion generation from relatively large (100-250 μm) initial droplets, which may have similarity to zvPSI, statistical fluctuations [35] was proposed as the most likely cause of the initial charge separation. More recently, mechanistic studies of an identical method to zvPSI-MS has also been published by Wleklinski et al [36] using a Monte Carlo simulation based on the statistical fluctuation to compare with experimental results.…”

Heterogeneous chemistry and reaction dynamics of the atmospheric oxidants, O3, NO3, and OH, on organic surfaces

“…Most recently, Beauchamp and coworkers have developed a method for generating controlled nanoliter-sized droplets for mass-spectrometric sampling using bursting bubble ionization and interfacial sampling with an acoustic transducer. 91 This method has been used to investigate the time-dependent ozonolysis of oleic acid.…”