Rapid Detection and Quantification of DMNB Vapors Using a Handheld Ion Mobility Spectrometer Operated near Ambient...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chemical Sensing

Background:

• Detection of plastic explosives is challenging due to low volatility of components like RDX and PETN.
• Volatile markers such as 2,3-dimethyl-2,3-dinitrobutane (DMNB) are used for indirect vapor detection.
• Need for rapid, sensitive, and portable detection methods for field applications.

Purpose of the Study:

• To develop and validate a rapid method for detecting and quantifying DMNB vapors.
• To assess the performance of a handheld ion mobility spectrometer (IMS) for this application.
• To evaluate the feasibility of using IMS for indirect detection of plastic explosives in field settings.

Main Methods:

• Utilized a handheld, ammonia-doped ion mobility spectrometer (IMS) with a corona discharge ionization source.
• Employed a twin drift-cell time-of-flight configuration for simultaneous positive and negative ion detection.
• Measured reduced mobility values (K0) and determined limits of detection (LOD) for DMNB vapor.

Main Results:

• DMNB generated distinct ion peaks in both positive (K0 = 1.42 cm2V-1s-1) and negative (K0 = 1.37 cm2V-1s-1) modes.
• Achieved high sensitivity with LODs of 1.4 ppb_v (positive) and 3.1 ppb_v (negative).
• Demonstrated rapid response (seconds) and a quantifiable range of 5-3000 ppb_v.

Conclusions:

• Portable IMS systems are capable of fast and sensitive trace vapor detection of DMNB.
• Simultaneous dual-polarity detection enhances selectivity and reliability for explosive marker identification.
• The method supports field-based screening for indirect detection of plastic explosives in scenarios like luggage inspection.