Scalable design of an IMS cross-flow micro-generator/ion detector

TL;DR

This paper introduces a scalable, miniaturized cross-flow ion-mobility spectrometry device with a novel ion focusing strategy, enabling high flow rates and improved resolution at sub-millimeter scales.

Contribution

It presents a new design for a cross-flow IMS device with an innovative ion focusing method, allowing operation at sub-millimeter scales with simplified construction.

Findings

Successful prototype testing with nitrogen gas

Simulation results with four different gases

Maintains laminar flow at high flow rates

Abstract

Ion-mobility spectrometry (IMS) is an analytical technique used to separate and identify ionized gas molecules based on their mobility in a carrier buffer gas. Such methods come in a large variety of versions that currently allow ion identification at and above the millimeter scale. Here, we present a design for a cross-flow-IMS method able to generate and detect ions at the sub-millimeter scale. We propose a novel ion focusing strategy and tested it in a prototype device using Nitrogen as a sample gas, and also with simulations using four different sample gases. By introducing an original lobular ion generation localized to a few ten of microns and substantially simplifying the design, our device is able to keep constant laminar flow conditions for high flow rates. In this way, it avoids the turbulences in the gas flow, which would occur in other ion-focusing cross-flow methods limiting their performance at the sub-millimeter scale. Scalability of the proposed design can contribute to improve resolving power and resolution of currently available cross-flow methods.