Detection of explosives using negative ion mobility spectrometry in air based on dopant-assisted thermal ionization.

The ionization source is an essential component of most explosive detectors based on negative ion mobility spectrometry. Conventional ion sources suffer from such inherent limitations as special safety regulations on radioactive sources or generating interfering ions (for non-radioactive sources) such as corona discharge operating in the air. In this study, a new negative ion source is introduced for ion mobility spectrometry that is based on thermal ionization and operates in the air, applicable to explosives detection. Our system consists of a heating filament powered by an isolated power supply connected to negative high voltage. The ionization is assisted by doping chlorinated compounds in the gas phase using chlorinated hydrocarbons in contact with the heating element to yield Cl- reactant ions. Several chlorinated hydrocarbons are evaluated as the reagent chemicals for providing Cl- reactant ions, of which CCl4 is identified as the best ionizing reagent. The ion source is evaluated by recording the ion mobility spectra of common explosives, including TNT, RDX, and PETN in the air. A detection limit of 150 pg is obtained for TNT. Compared to other ionization sources, the new source is found to be low-cost, simple, and long-lived, making it suited to portable explosives detection devices.

[1]  H. Hill,et al.  Comparison of reactant and analyte ions for ⁶³Nickel, corona discharge, and secondary electrospray ionization sources with ion mobility-mass spectrometry. , 2013, Talanta.

[2]  M. Tabrizchi.  Thermal ionization ion mobility spectrometry of alkali salts. , 2003, Analytical chemistry.

[3]  Anthony J. Midey,et al.  Improved analysis of explosives samples with electrospray ionization-high resolution ion mobility spectrometry (ESI-HRIMS) , 2010 .

[4]  A. H. Lawrence,et al.  Detection of ethylene glycol dinitrate vapors by ion mobility spectrometry using chloride reagent ions , 1988 .

[5]  David R. Lide,et al.  CRC HANDBOOK of THERMOPHYSICAL and THERMOCHEMICAL DATA , 1994 .

[6]  T. Khayamian,et al.  Analysis of 2,4,6-trinitrotoluene, pentaerythritol tetranitrate and cyclo-1,3,5-trimethylene-2,4,6-trinitramine using negative corona discharge ion mobility spectrometry. , 2003, Talanta.

[7]  Š. Matejčík,et al.  Interactions of multiple reactant ions with 2,4,6-trinitrotoluene studied by corona discharge ion mobility-mass spectrometry , 2015 .

[8]  John R. Griffiths,et al.  Ion mobility spectrometry: a review. Part 1. Structural analysis by mobility measurement , 2004 .

[9]  Sehwan Park,et al.  Analysis of explosives using corona discharge ionization combined with ion mobility spectrometry-mass spectrometry. , 2014, Talanta.

[10]  J. Todd,et al.  Alternative reagent ions for plasma chromatography , 1984 .

[11]  Š. Matejčík,et al.  Laser desorption with corona discharge ion mobility spectrometry for direct surface detection of explosives. , 2014, The Analyst.

[12]  A. Bell,et al.  Reverse flow continuous corona discharge ionisation applied to ion mobility spectrometry , 2002 .

[13]  Safa Kasap,et al.  Principles of electronic materials and devices , 2000 .

[14]  Li Jian-ping,et al.  A novel surface ionization source for ion mobility spectrometer. , 2007, Analytica chimica acta.

[15]  H H Hill,et al.  Analysis of explosives using electrospray ionization/ion mobility spectrometry (ESI/IMS). , 2000, Talanta.

[16]  H H Hill,et al.  Evaluation of suspected interferents for TNT detection by ion mobility spectrometry. , 2001, Talanta.

[17]  M. Dresser.  The Saha‐Langmuir Equation and its Application , 1968 .

[18]  M. Tabrizchi,et al.  An alkali ion source based on graphite intercalation compounds for ion mobility spectrometry , 2008 .

[19]  Weiguo Wang,et al.  Dopant-assisted negative photoionization ion mobility spectrometry for sensitive detection of explosives. , 2013, Analytical chemistry.

[20]  Herbert H Hill,et al.  Secondary electrospray ionization-ion mobility spectrometry for explosive vapor detection. , 2004, Analytical chemistry.

[21]  M. Tabrizchi,et al.  Application of ion mobility spectrometry in study of surfactants adsorbed on different dish surfaces , 2014, International Journal for Ion Mobility Spectrometry.

[22]  T. Khayamian,et al.  Design and optimization of a corona discharge ionization source for ion mobility spectrometry , 2000 .

[23]  M. Tabrizchi,et al.  Combined corona discharge and UV photoionization source for ion mobility spectrometry. , 2012, Talanta.

[24]  Frank J. Kuja,et al.  Interfacing an ion mobility spectrometry based explosive trace detector to a triple quadrupole mass spectrometer. , 2011, Analytical chemistry.

[25]  W. B. Knighton,et al.  Resolving interferences in negative mode ion mobility spectrometry using selective reactant ion chemistry. , 2001, Talanta.

[26]  M. Tabrizchi,et al.  A novel electron source for negative ion mobility spectrometry , 2002 .

[27]  Hu Chaoqun,et al.  Negative photoionization chloride ion attachment ion mobility spectrometry for the detection of organic acids , 2014 .

[28]  Peter de B. Harrington,et al.  Rapid multivariate curve resolution applied to identification of explosives by ion mobility spectrometry , 2001 .

[29]  Yun-ki Kim,et al.  Negative Ion Formation of Pentaerythritol Tetranitrate in Atmospheric Pressure Chemical Ionization-Mass Spectrometry and in Corona Discharge Ionization-Ion Mobility Spectrometry , 2011 .

[30]  Gary A. Eiceman,et al.  Advances in Ion Mobility Spectrometry: 1980–1990 , 1991 .

[31]  M. Tabrizchi,et al.  Detection of explosives by positive corona discharge ion mobility spectrometry. , 2010, Journal of hazardous materials.

[32]  N. Carpita,et al.  Analysis of carbohydrates by atmospheric pressure chloride anion attachment tandem mass spectrometry , 2013 .