Multiplexing of Electrospray Ionization Sources Using Orthogonal Injection into an Electrodynamic Ion Funnel

Abstract

In this contribution, we report an efficient approach to multiplex electrospray ionization (ESI) sources for applications in analytical and preparative mass spectrometry. This is achieved using up to four orthogonal injection inlets implemented on the opposite sides of an electrodynamic ion funnel interface. We demonstrate that both the total ion current transmitted through the mass spectrometer and the signal-to-noise ratio increase by 3.8-fold using four inlets compared to one inlet. The performance of the new multiplexing approach was examined using different classes of analytes covering a broad range of mass and ionic charge. A deposition rate of >10 μg of mass-selected ions per day may be achieved by using the multiplexed sources coupled to preparative mass spectrometry. The almost proportional increase in the ion current with the number of ESI inlets observed experimentally is confirmed using gas flow and ion trajectory simulations. The simulations demonstrate a pronounced effect of gas dynamics on the ion trajectories in the ion funnel, indicating that the efficiency of multiplexing strongly depends on gas velocity field. The study presented herein opens up exciting opportunities for the development of bright ion sources, which will advance both analytical and preparative mass spectrometry applications.

Navigate Flying Molecular Elephants Safely to the Ground: Mass-Selective Soft Landing up to the Mega-Dalton Range by Electrospray Controlled Ion-Beam Deposition

“… 43 , 147 , 151 , 152 Additionally, this allows for multiple and multiplexed spray systems in parallel. 150 , 153 …”

A Preparative Mass Spectrometer to Deposit Intact Large Native Protein Complexes

“…In addition to the requirements for ESI mass spectrometry, ES-IBD needs an intense ion beam ,− with well-defined energy distribution to enable fast sample preparation with controlled landing energy. The width of the beam-energy distribution is crucial, as it defines the collision energy distribution and limits the landing energy range.…”

A preparative mass spectrometer to deposit intact large native protein complexes

“…It enables new reaction pathways 33,34 and surface modifications. 35 In addition to the requirements for ESI mass spectrometry, ES-IBD needs an intense ion beam 18,[36][37][38] with well-defined energy distribution, to enable fast sample preparation with controlled landing energy. The width of the beam-energy distribution is crucial, as it defines the collision energy distribution and limits the landing energy range.…”

“…Currently, the barrier to widespread use of ES-IBD is still high and there is no commercial instrument available. Academic instrument developers have designed preparative MS mainly for small and medium size molecule deposition 20,37,40,[45][46][47][48] and only few of these instruments can handle native proteins complexes. 2,9,28 To be universally useful for molecular ion-beam deposition, ES-IBD instruments need to be good mass spectrometers, and have a high beam current in addition to the features needed for beam control and deposition.…”