Advances in Ionization for Mass Spectrometry

Self Cite

110

Together with my group and collaborators, I have been fortunate to have had a key role in the discovery of new ionization processes that we developed into new flexible, sensitive, rapid, reliable, and robust ionization technologies and methods for use in mass spectrometry (MS). Our current research is focused on how best to understand, improve, and use these novel ionization processes which convert volatile and nonvolatile compounds from solids or liquids into gas-phase ions for analysis by MS using e.g. mass selected fragmentation and ion mobility spectrometry to provide reproducible, accurate, and improved mass and drift time resolution. In my view, the apex was the discovery of vacuum matrix-assisted ionization (vMAI) in 2012 on an intermediate pressure matrix-assisted laser desorption/ionization (MALDI) source without the use of a laser, high voltages, or any other added energy. Only exposure of the matrix:analyte to the sub-atmospheric pressure of the mass spectrometer was necessary to initiate ionization. These findings were initially rejected by three different scientific journals, with comments related to 'how can this work?', 'where do the charges come from?', and 'it is not analytically useful'. Meanwhile, we, and others have demonstrated analytical utility without a complete understanding of the mechanism. In reality, MALDI and electrospray ionization are widely used in science and their mechanisms are still controversially discussed despite use and optimization of now 30 years. This Perspective covers applications, and mechanistic aspects of the novel ionization processes for use in MS that guided us in instrument developments, and provides our perspective on how they relate to traditional ionization processes.

Section: Fundamentals and Mechanistic Aspectsmentioning

confidence: 99%

“…The success of mass spectrometry (MS) depends on converting compounds into gas‐phase ions . The ability to achieve this from volatile, nonvolatile, small, and large compounds with high sensitivity has not only driven the expansion of MS, but also science; most notably in the life sciences.…”

Section: Introduction To Old and New Ionization Processes And Contentmentioning

confidence: 99%

Novel ionization processes for use in mass spectrometry: ‘Squeezing’ nonvolatile analyte ions from crystals and droplets

Trimpin

2019

Self Cite

110

“…Ambient ionization mass spectrometry techniques use ionization in open laboratory air to generate mass spectra of complex mixtures. Over 40 different types of ambient ionization techniques have been developed in the past decade . Some of these methods include atmospheric solids analysis probe (ASAP), direct analysis in real time (DART), desorption electrospray ionization (DESI) and extractive electrospray ionization (EESI) …”

Section: Introductionmentioning

confidence: 99%

A cautionary note on the effects of laboratory air contaminants on ambient ionization mass spectrometry measurements

Kumbhani

Wingen

Perraud

et al. 2017

“…Different from the traditional capillary ESI method, the ESI-based ambient ionization methods use non-capillary solid substrates as the electrospray emitter, and then a high voltage is applied to the solution which is put at the tip of the solid material where electrospray is induced. [5][6][7][8] This technique widened the material range of electrospray emitters, including copper wire, 9 optical fibers, 9 tungsten oxide wire, 10 carbon fiber, 11 stainless steel needles, 12 wooden tips, 13 PMMA, 14 paper, 15,16 fabrics and cellulose sponge, 17 etc. Meanwhile, these materials have shown their own exceptional advantages in the operating process.…”

Section: Introductionmentioning

confidence: 99%

Study on properties of wooden capillary electrospray ionization mass spectrometry

Lin

Yan

et al. 2020

Rationale In view of the unique properties of wooden materials as electrospray emitters, a novel wooden capillary electrospray ionization (WC‐ESI) device was fabricated. The performance of a wooden capillary as an electrospray emitter was investigated by using a wooden capillary instead of the metal emitter of commercial ESI sources. Methods The mass spectrometric measurement of baicalein, emodin and myoglobin was carried out by using wooden capillary (WC) and metal capillary (MC) ESI sources. Contrasting analysis of signal intensity between WC and MC electrospray ionization mass spectrometry (ESI‐MS) was implemented at different sample flow rates. The effect of WC‐ESI‐MS and MC‐ESI‐MS was evaluated experimentally with electrospray solutions in different solvent ratios. Results Generally, the signal generated by WC‐ESI‐MS was much stronger than that obtained by MC‐ESI‐MS. In particular, the MS signal in negative ion mode was very strong, which may solve the long‐standing problem of low MS signals in negative ion mode, and fully improve the detection efficiency of ESI‐MS. Conclusions The signal intensity produced by WC‐ESI‐MS is significantly higher than that from MC‐ESI‐MS, and polymerization and electrolysis are reduced; therefore, the spectra become simpler. In addition, it is also tolerant to high flow rates and high aqueous phase samples.