TY - JOUR
T1 - Applications of switching reagent ions in proton transfer reaction mass spectrometric instruments for the improved selectivity of explosive compounds
AU - Sulzer, Philipp
AU - Agarwal, Bishu
AU - Jürschik, Simone
AU - Lanza, Matteo
AU - Jordan, Alfons
AU - Hartungen, Eugen
AU - Hanel, Gernot
AU - Märk, Lukas
AU - Märk, Tilmann D.
AU - Gonzalez Mendez, Ramon
AU - Watts, Peter
AU - Mayhew, Chris A.
PY - 2013
Y1 - 2013
N2 - Here we demonstrate the use of a switchable reagent ion proton transfer reaction mass spectrometry (SRI-PTR-MS) instrument to improve the instrument's selectivity for the detection of the explosive compounds 2,4,6 trinitrotoluene (TNT), 1,3,5 trinitrobenzene (TNB), pentaerythritol tetranitrate (PETN), and cyclotrimethylenetrinitramine (RDX). Selectivity is improved owing to the production of different product ions resulting from changes in the reagent ion-molecule chemistry. To be of use as an analytical tool for homeland security applications, it is important that the reagent ions (and hence product ions) can be rapidly changed (within seconds) from H3O+ to another dominant ion species if the technology is to be acceptable. This paper presents measurements that show how it is possible to rapidly switch the reagent ion from H3O+ to either O2
+ or NO+ to enhance selectivity for the detection of the four explosives named above. That switching reagent ions can be done quickly results from the fact that the recombination energies of O2
+ and NO + are less than the ionisation potential of H2O, i.e. charge transfer cannot occur which otherwise would result in ions that can react efficiently with water (e.g. H2O+ + H2O → H3O+ + OH) leading to H3O+ becoming the dominant reagent ion. Reaction processes observed are non-dissociative charge transfer (O2
+ with TNT and TNB), dissociative charge transfer (O2
+ with TNT) and adduct formation (NO+ with PETN and RDX). O2
+ is found to be unreactive with PETN and RDX, and under the conditions operating in the reaction region of the PTR-MS only a low signal associated with NO+· TNT was observed. No NO+·TNB was detected.
AB - Here we demonstrate the use of a switchable reagent ion proton transfer reaction mass spectrometry (SRI-PTR-MS) instrument to improve the instrument's selectivity for the detection of the explosive compounds 2,4,6 trinitrotoluene (TNT), 1,3,5 trinitrobenzene (TNB), pentaerythritol tetranitrate (PETN), and cyclotrimethylenetrinitramine (RDX). Selectivity is improved owing to the production of different product ions resulting from changes in the reagent ion-molecule chemistry. To be of use as an analytical tool for homeland security applications, it is important that the reagent ions (and hence product ions) can be rapidly changed (within seconds) from H3O+ to another dominant ion species if the technology is to be acceptable. This paper presents measurements that show how it is possible to rapidly switch the reagent ion from H3O+ to either O2
+ or NO+ to enhance selectivity for the detection of the four explosives named above. That switching reagent ions can be done quickly results from the fact that the recombination energies of O2
+ and NO + are less than the ionisation potential of H2O, i.e. charge transfer cannot occur which otherwise would result in ions that can react efficiently with water (e.g. H2O+ + H2O → H3O+ + OH) leading to H3O+ becoming the dominant reagent ion. Reaction processes observed are non-dissociative charge transfer (O2
+ with TNT and TNB), dissociative charge transfer (O2
+ with TNT) and adduct formation (NO+ with PETN and RDX). O2
+ is found to be unreactive with PETN and RDX, and under the conditions operating in the reaction region of the PTR-MS only a low signal associated with NO+· TNT was observed. No NO+·TNB was detected.
KW - Detection of explosives
KW - PETN
KW - PTR-MS
KW - RDX
KW - TNB
KW - TNT
UR - http://www.scopus.com/inward/record.url?scp=84888293978&partnerID=8YFLogxK
U2 - 10.1016/j.ijms.2013.05.004
DO - 10.1016/j.ijms.2013.05.004
M3 - Article
AN - SCOPUS:84888293978
SN - 1387-3806
VL - 354-355
SP - 123
EP - 128
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
ER -