Ion Manipulation in Open Air Using 3D-Printed Electrodes
- PDF / 2,880,250 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 49 Downloads / 225 Views
J. Am. Soc. Mass Spectrom. (2019) DOI: 10.1007/s13361-019-02307-2
RESEARCH ARTICLE
Ion Manipulation in Open Air Using 3D-Printed Electrodes Kiran Iyer,1 Brett M. Marsh,1 Grace O. Capek,1 Robert L. Schrader,1 Shane Tichy,2 R. Graham Cooks1 1
Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA Agilent Technologies, 5301 Stevens Creek Blvd, Santa Clara, CA 95051, USA
2
Abstract. Ambient ionization techniques provide a way to sample materials via creation of ions in the air. However, transferring and focusing of these ions is typically done in the reduced pressure environment of the mass spectrometer. Spray-based ambient ionization sources require relatively large distances between the source and mass spectrometer inlet for effective desolvation, resulting in a small fraction of the ions being collected. To increase the efficiency of ion transfer from atmosphere to vacuum, 3D-printed focusing devices made of conductive carbon nanotube doped polymers have been designed and evaluated for ion focusing in air. Three main classes of electrodes are considered: (i) conic section electrodes (conical, ellipsoidal, and cylindrical), (ii) simple conductive and nonconductive apertures, and (iii) electrodes with complex geometries (straight, chicane, and curved). Simulations of ion trajectories performed using the statistical diffusion simulation (SDS) model in SIMION showed a measure of agreement with experiment. Cross-sectional images of ion beams were captured using an ion detecting chargecoupled device (IonCCD). After optimization, the best arrangements of electrodes were coupled to an Agilent Ultivo triple quadrupole to record mass spectra. Observations suggest that electrode geometry strongly influences ion trajectories in air. Non-conductive electrodes also assisted in focusing, due to charge buildup from ion deposition. We also observed minimal spreading of the ion packet after exiting the focusing electrodes indicating that atmospheric collisions do not reduce collimation of the beam. The study suggests that high pressures need not be viewed as a hindrance to ion transport, but as a potentially useful force. Keywords: Ambient ionization, Additive manufacturing, Ion focusing, Triple quadrupole, Ion transmission Received: 20 May 2019/Revised: 31 July 2019/Accepted: 2 August 2019
Introduction
T
Kiran Iyer and Brett M. Marsh contributed equally to this work. Dedicated to Prof. Helmut Schwarz in admiration of the quality and quantity of his science Electronic supplementary material The online version of this article (https:// doi.org/10.1007/s13361-019-02307-2) contains supplementary material, which is available to authorized users. Correspondence to: Shane Tichy; e-mail: [email protected], R. Cooks; e-mail: [email protected]
he ability to manipulate ions in the air is of great importance in mass spectrometry (MS) due to the widespread adoption of electrospray ionization (ESI) [1] and of ambient ionization techniques [2–6] as the ionization methods of choice for many users. Typically, ions ar
Data Loading...
