A real-time ion mobility sensor developed to detect contaminants and explosives is reliable, sensitive, robust, and inexpensive. The technology improves sensitivity and reduces false alarms for threat agents, and can identify chemicals with a sensitivity of five parts per billion.
The device solves problems of long-term monitoring by combining ion mobility spectrometry and differential mobility spectrometry with membrane separation. Current methods for long-term monitoring are complex, expensive, and time-consuming. Ion mobility spectrometry cannot identify chlorinated hydrocarbons, has high false alarm rates, and is vulnerable to interference. It is also easily affected by moisture, resulting in false alarms. Similarly, differential mobility spectrometry alone cannot monitor chlorinated hydrocarbons.
By coupling the two methods, the new system reduces false alarms, separates interferents from chlorinated hydrocarbons, and can successfully identify contaminants such as chlorinated hydrocarbons, perchlorates, and explosives. In brief, ion mobility spectrometry filters the safe species, while differential mobility spectrometry separates the contaminants and explosives.
Benefits of the system include compact size, ambient atmosphere for operation, no vacuum, remote reporting and control, and reduction of false alarms.