Simulation aided design of a low cost ion mobility spectrometer based on printed circuit boards

Abstract

Miniaturized low-cost drift tubes with high analytical performance are a key component for the design of powerful and mass-deployable hand-held ion mobility spectrometers. Thus, a simple model that estimates the influence of the geometrical dimensions on the analytical performance is highly desirable for an effective design process. In this work, we present a simple procedure to predict peak distortion based on only the electrical field distribution inside the drift tube, which can be rapidly simulated using the finite element method. A simulation of the ion motion is not required. Based on these results, we developed an ion mobility spectrometer manufactured entirely from standard printed circuit boards (PCB). Since no additional components were used apart from electrical and gas connectors, ion source and metal grids, the presented ion mobility spectrometer is very simple and inexpensive. Nevertheless, the design provides a resolving power of 82 at a drift length of 50 mm and a drift voltage of 3 kV using a tritium ion source and a field switching shutter. The limits of detection for one second of averaging are 80 ppt v for acetone, 35 ppt v for dimethyl methylphosphonate and 180 ppt v for methyl salicylate.

Miniaturized high-performance drift tube ion mobility spectrometer

“…Some designs are based on low temperature cofired ceramic (LTCC) [8]. Other designs use stacked electrode-insulator-pairs [6,9] or printed circuit boards [10,11]. However, the key challenge of miniaturization is to maintain the analytical performance of the IMS, which strongly depends on the geometrical dimensions of the drift tube [10,12].…”

Ultra-high-resolution ion mobility spectrometry—current instrumentation, limitations, and future developments

“…In order to measure the ion mobility, a small packet of ions is injected by an ion shutter into a drift tube with a constant electric field and the drift time required to reach the detector is measured. Drift tubes can be manufactured in a wide variety of sizes and from a wide variety of materials such as resistive glass tubes [59,60], low temperature co-fired ceramics (LTCC) [61], printed circuit boards (PCB) [62,63] or even 3D printing [64]. The expected drift time of an ion with ion mobility K through a drift tube of length L with the electric field E is given by eq.…”

High Kinetic Energy Ion Mobility Spectrometry (HiKE-IMS) at 40 mbar

“…For comparison, the length of the drift region of the previous presented HiKE-IMS 51 operated at 20 mbar is 306 mm. The table of content graphic shows a photograph of the reaction region of the HiKE-IMS, which is entirely built from standard printed circuit boards similar to the work of Bohnhorst et al 53 .The default operating parameters are listed in Table 1. Before assembly, all parts are thoroughly cleaned in an ultrasonic bath and afterwards stored in a vacuum oven at 80 °C for 24 h to prevent any outgassing during operation as this can significantly alter the ion population 54 .…”