Differential Mobility Spectrometry (DMS)

How do we build a rapid, portable, highly sensitive volatile chemical detection system?

Overview

The ability to measure trace chemicals in air or water quickly and accurately can be a matter of survival. Particularly in isolated locations, such as the International Space Station (ISS), collecting samples and sending them to a lab for analysis may be impractical, supplies of air or water limited and evacuation difficult. In January 2015, pressure sensors aboard the ISS erroneously signaled a potential ammonia leak, prompting NASA astronauts to move to the Russian side of the ISS. Draper’s onboard microAnalyzer™ device confirmed that ISS air quality was within safety parameters. Based on Differential Mobility Spectrometry (DMS) technology, Draper’s portable device detects trace vapors as low as a few parts per trillion.

Capabilities Used
Microsystems

Draper has designed and developed microelectronic components and systems going back to the mid-1980s. Our integrated, ultra-high density (iUHD) modules of heterogeneous components feature system functionality in the smallest form factor possible through integration of commercial-off-the-shelf (COTS) technology with Draper-developed custom packaging and interconnect technology. Draper continues to pioneer custom Microelectromechanical Systems (MEMS), Application-Specific Integrated Circuits (ASICs) and custom radio frequency components for both commercial (microfluidic platforms organ assist, drug development, etc.) and government (miniaturized data collection, new sensors, Micro-sats, etc.) applications.  Draper features a complete in-house iUHD and MEMS fabrication capability and has existing relationships with many other MEMS and microelectronics fabrication facilities. 

Biomedical Solutions

Draper’s Biomedical Solutions capability centers on the application of microsystems, miniaturized electronics, computational modeling, algorithm development and image and data analytics applied to a range of challenges in healthcare and related fields. Draper fills that critical engineering niche that is required to take research or critical requirements and prototype or manufacture realizable solutions.  Some specific examples are MEMS, microfluidics and nanostructuring applied to the development of wearable and implantable medical devices, organ-assist devices and drug-delivery systems. Novel neural interfaces for prosthetics and for treatment of neurological conditions are being realized through a combination of integrated miniaturized electronics and microfabrication technologies.

Smaller, less complex and less expensive than a mass spectrometer, a DMS device performs similar high-quality chemical measurements immediately in situ. As a “tunable ion filter,” a DMS device can step through numerous “tuning” parameters to reject interferents and to select compounds of interest, significantly reducing rates of false positives and false negatives. Unlike other technologies, DMS does not require hardware modifications (coatings, wavelength changes, etc.) to detect new compounds of interest.

After Draper’s DMS device has been installed in the field, users can expand its detection capability remotely via wired or wireless communication. This feature makes Draper’s DMS device especially useful in hard-to-service locations, such as submarines at sea.

 

The microAnalyzer™ v2 can detect volatile organic chemicals at the parts-per-trillion level.

 

Draper’s DMS detector supports multiple system configurations. One configuration enables continuous air monitoring with immediate alerting capability, useful for soldiers on the battlefield or firefighters monitoring for toxins; this configuration is sensitive to chemical traces at the parts-per-billion level. Another configuration has a built-in sample concentrator and gas chromatograph enabling sensitivity at the parts-per-trillion level. Called the microAnalyzer™, its periodic testing cycle lasts seconds to approximately 10 minutes, depending on the application.

 

The microAnalyzer™ v2 units aboard the International Space Station monitor cabin air quality to protect the health and safety of astronauts. Photo credit NASA.

 

Either of these configurations can use a front end to sample liquids. DMS sensors also may be an extremely valuable prefilter to orthogonal tandem detectors (e.g., mass spectrometer).

Potential applications for Draper’s DMS devices include medical use (breath analysis at home, doctor’s office or hospital), water analysis, threat detection and confined space monitoring.

 

Aboard the International Space Station MicroAnalyzer™ units are installed in pairs to measure for different types of chemical traces.

 

Technical Contact
Ken Markoski

General DMS Inquiries

John West

Space, Water Analysis and Confined Space Monitoring Applications

Anthony Coston

Program Office