| Use: | Ion mobility spectrometry (IMS) is a technique used to detect and characterize organic
vapors in air. Recent development of portable IMS detectors might make the technique an
alternative to FID and GC. Safe for thermally sensitive compounds. See 6.2.11 for use with VOCs, SVOCs, and pesticides. |
Description:
A sampling pump draws air through a semi-permeable membrane, which is selected to exclude or attenuate possible interferents. The sample is ionized in a reaction region through interaction with a weak plasma of positive and negative ions produced by a radioactive source. A shutter grid allows periodic introduction of the ions into a drift tube, where they separate based on charge, mass, and shape with the arrival time recorded by a detector (ion mobility spectrometry analysis is based on analyte separations resulting from ionic mobilities rather than ionic masses). The identity of the molecules is determined using a computer to match the signals to IMS signatures held in memory. If the IMS signature is known, it is also possible to program the instrument to detect specific compounds of interest. IMS operates at atmospheric pressure, a characteristic that has practical advantages over mass spectrometry, including smaller size, lower power requirements, less weight, and ease of use.
Analytes:
10. Explosives
Media:
| Soil/Sediment | Water | Gas/Air |
| Requires extraction to liquid or gas phase | Requires extraction to liquid or gas phase | BETTER |
| Selectivity: | Technique measures the specific contaminant directly. |
| Susceptibility to Interference: | High. |
| Detection Limits : | 500+ ppm (soil); 100+ ppm (water). |
| Turnaround Time per Sample: | Hours. |
| Applicable To: | |||
| Screen/Identify | Characterize Concentration/Extent | Cleanup Performance | Long-Term Monitoring |
| BETTER | SERVICEABLE | SERVICEABLE | SERVICEABLE |
| Quantitative Data Capability: | Produces quantitative data. |
| Technology Status: | Commercially available technology with limited field experience. |
| Certification/Verification: | Technology has not participated in CalEPA certification and/or CSCT verification program. |
| Relative Cost per Analysis: | Most expensive. |
Limitations:
ASTM Standards/EPA Methods:
No applicable ASTM standards or EPA methods are cited for this technology.
| Previous Page | Sample Access/Collection Matrix | Sample Analysis Matrix | Home | Areas of Interest | Next Page |