Overview

The history behind microDMx™ technology, (Differential Mobility), has its roots in the former Soviet Union where work was conducted in applying high field strengths. Published work by researchers such as Erkinjon Nazarov et al. illustrate the foundation of the technology. This initial work was often referred to as FAIMS,    (Field Asymetric Ion Mobility Spectrometry). Although the roots of microDMx™ technology can be traced back to FAIMS, operationally and performance wise it is very different.

Work carried out at The Charles Stark Draper Laboratory by Raanan Miller et al. took the original concept of FAIMS and applied MEMS and mircofabrication technology to produce the microDMx™ chip capable of detecting and separating a wide variety of compounds. While the MEMS work progressed at The Charles Stark Draper Laboratory additional work on some of the chemistry behind the detection mechanisms was being conducted at New Mexico State University for Draper. Gary Eiceman a world renowned expert on mobility spectrometry was involved in much of this work.

This early work together with MEMS and mircofabrication methods has resulted in the microDMx™ chip which is being commercialized and developed by Sionex today. Sionex operates with a worldwide exclusive commercialization license agreement from The Charles Stark Draper Laboratory.

Fundamental advantages of microDMx™ chips are being realized today and are incorporated into all Sionex products.

	Higher sensitivity
	Higher specificity
	Lower manufacturing costs due to MEMS manufacturing
	Small compact "chip-sized" package.

These technical advantages translate to important product advantages for the end users.

	Lower incidence of false positives
	High sensitivity while maintaining specificity
	Highly compact portable or personal sized products.

microDMx™ technology separates & detects ionized compounds based on their differential mobilities through the sensor chip. Ionized compounds have mobilities which are a function of their charge, mass and cross-sectional area. By applying an RF and DC field to the sensor chip it can act as a filter selecting a chosen ion or collection of ions. The applied DC & RF fields can be used as parameters to identify the ions together with additional information (field dependence) which is unique to microDMx™ technology.

The microDMx™ chip samples close to 100% of the ionized species resulting in increased sensitivity whereas conventional IMS samples as little as 1%. Conventional IMS also suffers from the inability to positively identify ions because it only uses one parameter - time, whereas microDMx™ technology uses at least 4 independent parameters simultaneously!