Ion/molecule reactions of atmospheric ions with dimethyl-methylphosphonate

Chatterjee, B.; Tosh, R; Johnsen, Rainer

doi:10.1016/0168-1176(91)80080-7

Cited by 4 publications

(25 citation statements)

References 11 publications

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“…19 The current SIFT rate constant is close to the collision rate constant value, but it is 4 times greater than the previous SIFDT experimental value. 19 The current experiments use a very dilute mixture of DMMP in helium that reacts with the selected reactant ion for a fixed reaction time while the flow of the mixture is varied. The Chatterjee et al experiments, on the other hand, have used a neat DMMP sample cooled in a dry ice bath at a concentration determined by measuring the pressure of DMMP with a capacitance manometer.…”

Section: Resultssupporting

confidence: 51%

“…14 Lum and Grabowski have studied negative ion reactions with DMMP in a flowing afterglow to compare the reactivity of the P-O and C-O bonds, 18 while Johnsen and co-workers have examined the reactions of several air plasma cations with DMMP in a selected ion flow drift tube (SIFDT). 19 CIMS detection of CWAs benefits from not having to pretreat the gas sample to be analyzed, only requiring the production of easily generated reactant ions that have both large rate constants and unique product ion distributions upon reaction with CWAs to achieve sensitive and selective detection. To find new ion-molecule reactions that meet these two criteria for the GX series agents, a study of experimental rate constants and product ion branching ratios has been conducted using a selected ion flow tube (SIFT) at 298 K for a variety of positive and negative ions reacting with the GX structural surrogate, DMMP.…”

mentioning

confidence: 99%

“…Chatterjee et al have also found this product to be one of the two major product ions in a SIFDT, but this product accounts for 34% of their product ions, with the rest appearing as lower mass product ions at thermal energies with a strong dependence on the center-ofmass kinetic energy. 19 A minor product ion channel at 125 amu giving OPO-(OCH 3 ) 2…”

mentioning

confidence: 99%

“…+ is OP(O)(OCH 3 ) + at m/z ) 94 amu, in agreement with the SIFDT results. 19 The CH 3 O product fragment formed during the creation of the 125 amu product could then abstract one of the CH 3 O groups to form CH 3 OOCH 3 and OP(O)(OCH 3 ) + , possibly in a sequential-type reaction that is overall 283 kJ mol -1 exothermic. As shown in Table 1, three other 94 amu product ion isomers can be formed exothermically from the net loss of CH 2 O with different combinations of H migration and rearrangement.…”

mentioning

confidence: 99%

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Kinetics of Ion−Molecule Reactions with Dimethyl Methylphosphonate at 298 K for Chemical Ionization Mass Spectrometry Detection of GX

Midey¹,

Miller²,

Viggiano³

2009

J. Phys. Chem. A

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Kinetics studies of a variety of positive and negative ions reacting with the GX surrogate, dimethyl methylphosphonate (DMMP), were performed. All protonated species reacted rapidly, that is, at the collision limit. The protonated reactant ions created from neutrals with proton affinities (PAs) less than or equal to the PA for ammonia reacted exclusively by nondissociative proton transfer. Hydrated H(3)O(+) ions also reacted rapidly by proton transfer, with 25% of the products from the second hydrate, H(3)O(+)(H(2)O)(2), forming the hydrated form of protonated DMMP. Both methylamine and triethylamine reacted exclusively by clustering. NO(+) also clustered with DMMP at about 70% of the collision rate constant. O(+) and O(2)(+) formed a variety of products in reactions with DMMP, with O(2)(+) forming the nondissociative charge transfer product about 50% of the time. On the other hand, many negative ions were less reactive, particularly, SF(5)(-), SF(6)(-), CO(3)(-), and NO(3)(-). However, F(-), O(-), and O(2)(-) all reacted rapidly to generate m/z = 109 amu anions (PO(3)C(2)H(6)(-)). In addition, product ions with m/z = 122 amu from H(2)(+) loss to form H(2)O were the dominant ions produced in the O(-) reaction. NO(2)(-) underwent a slow association reaction with DMMP at 0.4 Torr. G3(MP2) calculations of the ion energetics properties of DMMP, sarin, and soman were also performed. The calculated ionization potentials, proton affinities, and fluoride affinities were consistent with the trends in the measured kinetics and product ion branching ratios. The experimental results coupled with the calculated ion energetics helped to predict which ion chemistry would be most useful for trace detection of the actual chemical agents.

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Section: Resultssupporting

confidence: 51%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Kinetics of Ion−Molecule Reactions with Dimethyl Methylphosphonate at 298 K for Chemical Ionization Mass Spectrometry Detection of GX

Midey¹,

Miller²,

Viggiano³

2009

J. Phys. Chem. A

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“…A field in the direction of the mass spectrometer inlet transports the (Beauchamp, et al, 2008) ions formed to the inlet. The concept of proton transfer reaction for mass spectrometry is well known and has already been used in the 1960s (Moran & Hamill, 1963) for the investigation of ion-molecule reactions (Chatterjee et al, 1991). PTR-MS in the configuration shown in Figure 5 has been developed by Hansel et al (1995).…”

Section: Proton Transfer Reaction Mass Spectrometrymentioning

confidence: 99%

Real‐time monitoring of exhaled drugs by mass spectrometry

Berchtold

Bosilkovska

Daali

et al. 2013

Mass Spectrometry Reviews

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Future individualized patient treatment will need tools to monitor the dose and effects of administrated drugs. Mass spectrometry may become the method of choice to monitor drugs in real time by analyzing exhaled breath. This review describes the monitoring of exhaled drugs in real time by mass spectrometry. The biological background as well as the relevant physical properties of exhaled drugs are delineated. The feasibility of detecting and monitoring exhaled drugs is discussed in several examples. The mass spectrometric tools that are currently available to analyze breath in real time are reviewed. The technical needs and state of the art for on-site measurements by mass spectrometry are also discussed in detail. Off-line methods, which give support and are an important source of information for real-time measurements, are also discussed. Finally, some examples of drugs that have already been successfully detected in exhaled breath, including propofol, fentanyl, methadone, nicotine, and valproic acid are presented. Real-time monitoring of exhaled drugs by mass spectrometry is a relatively new field, which is still in the early stages of development. New technologies promise substantial benefit for future patient monitoring and treatment.

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