TY - JOUR
T1 - Sensitivity and selectivity of switchable reagent ion soft chemical ionization mass spectrometry for the detection of picric acid
AU - Agarwal, Bishu
AU - Gonzalez Mendez, Ramon
AU - Lanza, Matteo
AU - Sulzer, Philipp
AU - Märk, Tilmann D.
AU - Thomas, Neil
AU - Mayhew, Chris A.
PY - 2014/9/18
Y1 - 2014/9/18
N2 - We have investigated the reactions of NO+, H3O+, O2+, and Kr+ with picric acid (2,4,6 trinitrophenol, C6H3N3O7, PiA) using a time-of-flight mass spectrometer with a switchable reagent ion source. NO+ forms a simple adduct ion PiA·NO+, while H3O+ reacts with PiA via nondissociative proton transfer to form PiAH+. In contrast, both O2+ and Kr+ react with PiA by nondissociative charge transfer to produce PiA+. For Kr+, we also observe dissociation of PiA, producing NO2+ with a branching percentage of approximately 40%. For the reagent ions H3O+ and O2+ (and operating the drift tube with normal laboratory air), we find that the intensities of the PiAH+ and PiA+ ions both exhibit a peak at a given drift-tube voltage (which is humidity dependent). This unusual behavior implies a peak in the detection sensitivity of PiA as a function of the drift-tube voltage (and hence E/N). Aided by electronic-structure calculations and our previous studies of trinitrotoluene and trinitrobenzene, we provide a possible explanation for the observed peak in the detection sensitivity of PiA.
AB - We have investigated the reactions of NO+, H3O+, O2+, and Kr+ with picric acid (2,4,6 trinitrophenol, C6H3N3O7, PiA) using a time-of-flight mass spectrometer with a switchable reagent ion source. NO+ forms a simple adduct ion PiA·NO+, while H3O+ reacts with PiA via nondissociative proton transfer to form PiAH+. In contrast, both O2+ and Kr+ react with PiA by nondissociative charge transfer to produce PiA+. For Kr+, we also observe dissociation of PiA, producing NO2+ with a branching percentage of approximately 40%. For the reagent ions H3O+ and O2+ (and operating the drift tube with normal laboratory air), we find that the intensities of the PiAH+ and PiA+ ions both exhibit a peak at a given drift-tube voltage (which is humidity dependent). This unusual behavior implies a peak in the detection sensitivity of PiA as a function of the drift-tube voltage (and hence E/N). Aided by electronic-structure calculations and our previous studies of trinitrotoluene and trinitrobenzene, we provide a possible explanation for the observed peak in the detection sensitivity of PiA.
UR - http://www.scopus.com/inward/record.url?scp=84921776782&partnerID=8YFLogxK
U2 - 10.1021/jp5010192
DO - 10.1021/jp5010192
M3 - Article
C2 - 24559481
AN - SCOPUS:84921776782
SN - 1089-5639
VL - 118
SP - 8229
EP - 8236
JO - The Journal of Physical Chemistry A
JF - The Journal of Physical Chemistry A
IS - 37
ER -