Technology

Ion Mobility Spectrometry

What is Ion Mobility Spectrometry (IMS)?

Ion Mobility Spectrometry (IMS) is an analytical technology that separates analyte mixtures into their component compounds and then detects what these compounds are.

Separation of compounds is based on the specific drift times that ionised compounds need to pass a fixed distance (drift tube) in a defined electric field. The drift time of each substance is determined by the mass and geometric structure of its own ions. These parameters determine the number and rate of collisions with the drift tube walls that, in turn, impact upon the speed of transit through the drift tube. An electrometer then measures the resulting ion current as a function of time.

IMS is an ideal tool to analyse gaseous and liquid headspace samples. Its ultra-sensitivity and rapidity make it ideal for situations where quick results are required, when compound levels are low or where analysis is better done on-site rather than in a laboratory.

Comparative specifications: IMS vs other techniques

Would you like to understand whether IMS is the right choice for your lab or application? This table may help you:

	TD/GC/MSD	PTR-TOF-MS	SIFT-MS	GC/IMS
Deployment	Laboratory	Laboratory	Laboratory	Lab & Point-of-Care
Mass range	1050 amu	20 – 180 amu	< 300 Da	< 1000 Da
Ions	positive	positive	positive	positive, negative
Detection limit	ppb_v-ppm_v	ppt_v	ppb_v	ppt_v-ppm_v
Gas consumption	Helium	Helium	Helium	Air
Vacuum pump needed	yes	yes	yes	no
Measurement time	60 – 120 min	30 min	30 min	10 min
Weight	96 kg	170 kg	212 kg	18 kg
Dimensions (cm x cm x cm)	88 x 56 x 50	56 x 130 x 78	90 x 72 x 88	45 x 35 x 28
Personnel needed for operation	Scientist	Scientist	Scientist	Technician

GC-IMS vs GC-MS

While IMS can be complimentary with many analytical techniques, it can often be seen as an alternative to GC-MS. So, how do they compare?

Performance

GC-IMS is ideal for detecting variations in known matrices
Rapidly detects small differences in complex samples
Faster and more reliable screening than human sensory panels
As sensitive as standard GC-MS for a wide range of VOCs
Inherent two-dimensional separation allows fast throughput of complex samples

Low ongoing cost of ownership

Simplicity of operation means the system just keeps running
Reproducibility and repeatability mean low frequency of calibration
Designed to run continuously in the lab or at-site
Requires only high purity nitrogen as carrier and drift gas
Can be operated by personnel with non-specialist training
Uses standard laboratory consumables
Routine maintenance conducted by end-user

At home, in the laboratory or on-site

Compact all in one solution (sampling, separation, detection and analysis in one box)
Easy to transport
Simple interchange between advanced user or turn-key interface
Ideal for remote locations
Can store data locally for interrogation or download, or transmit via a network
No vacuum pump to maintain

Intuitive software

The problem to be solved

Early and accurate detection of the presence of a disease in an individual is key to improving outcomes for patients and value for healthcare providers. Breath analysis is one of the technologies emerging from the realms of Big Data and computing advances that holds promise to make early detection of disease a reality. Early identification of metabolic disease processes would be a game changer for more effective treatment and management of infectious diseases, cancers and chronic lifestyles diseases, to name just a few conditions.

A role for Volatile Organic Compounds

Volatile organic compounds (VOCs) in exhaled breath contain large amounts of chemical information that reflect the biological mechanisms and metabolic processes at play within an individual at any given point in time. When analysed into metabolic profiles, this information can be used as a biomarker to detect the presence of disease condition.

Until recently, sufficiently sensitive analytical technology and computing power has not been available to be able to detect, quantify and extract patterns that can be associated with specified disease states from very low concentrations of compound. Imspex Medical’s GC-IMS technology addresses this gap.

Our GC-IMS technology

Our technology combines the analytical chemistry strengths of gas chromatography (GC) and Ion Mobility Spectrometry (IMS) with Big Data multivariate data analysis power. Analytical chemistry results are analysed with proprietary integrated software to identify digital compound signatures and to link these to given target disease indications.

Detection using this ultrasensitive method yields rapid and accurate results, even with low compound concentrations. It is robust and can be used in both centralised laboratories and for decentralised testing. This makes it equally applicable for use in environments ranging from laboratories through to community healthcare and mass screening situations.

Technical characteristics of GC-IMS

Ultrahigh sensitivity	Detection Limits in the low ppb (μg/m3) range for VOCs with heteroatoms like ketones, aldehydes, alcohols, amines, or halogenated compounds
High selectivity	Specific analyte ion drift times 2-Dimensional separation Full orthogonality
Flexibility	Capability to generate both positive and negative ions
Low Pressure Ionisation	Use of Atmospheric Pressure Ionisation (API)
GC parameters	High GC sampling frequency
Regulatory conformity with respect to ³H	No license for ³H source required according to EU directive 96/29 EURATOM Radiation protection officer not required
Confidence	High reproducibility
Gas supply	Nitrogen or synthetic air
Data analytics	Stand-alone data acquisition software and software suite for 3D GC-IMS data analysis

Our Technology

Our proprietary technology combines gas chromatography with ion mobility spectrometry to form a robust, selective and ultra-sensitive GC-IMS combination that has multiple research, industrial, environmental and medical applications.