Continuous detection of hydrazine and monomethylhydrazine using ion mobility spectrometry

Mobility resolution and mass analysis of ions from ammonia and hydrazine complexes with ketones formed in air at ambient pressure

“…In the latter case, the protonated hydrazone [MMH·H ϩ ·(ketone) Ϫ H 2 O] solvated by one and two ketone molecules was the only other significant ion. Acetone showed a similar behavior but MMH·H ϩ ·(ketone) 3 was of also present. Although protonated hydrazones and their ketone adducts were severely diminished in intensity with ketones throughout the instrument, 5-nonanone was theÅ exception.Å AsÅ shownÅ inÅ FigureÅ 3c,Å theÅ ionÅ m/z 331, MMH·H ϩ ·(C 9 H 18 O) 2 , is the most intense peak in the spectrum but the protonated hydrazone and its solvate, m/z 171 and 313, are also of high intensity.…”

“…The identities of the ions appearing in D and E may be surmised from the linear correlation of drift time with ion mass for a homologousÅ seriesÅ [13].Å TheÅ driftÅ timeÅ forÅ E,Å whenÅ itÅ is assumed to be NH 4 ϩ (non) 4 , gives a linear fit with those for B and C and an equation for the line, t d (ms) ϭ 0.0279 u ϩ 9.148. The expected drift time for NH 4 ϩ (non) 3 (mass of 445 u) from this analysis should be 21.56 ms and so the peak D, with a drift time of 20.27 ms, was comprised mainly of ions that have spent 32% of drift time as NH 4 ϩ (non) 3 and 68% as NH 4 ϩ (non) 4 . In their initial work with ammonia and the hydrazines, Eiceman et al reported that the mobility of the complex for the ammonium ion and 5-nonanone had a drift time of 13.46 ms, and that NH 4 ϩ (non) and NH 4 ϩ (non) 2 were found in IMS/MS/MS measurements [4].Å ComparisonÅ mayÅ beÅ madeÅ withÅ theÅ presentÅ results using K o values obtained from drift times and eq 2 and eq 3.…”

“…For 5-nonanone, the largest peak was always m/z 299, (C 9 H 20 N 2 ) H ϩ (C 9 H 18 O), the solvated protonated hydrazone. The adduct ion HZ·H ϩ ·(non) 2 was the second largest peak, and there was a very small peak at m/z 459 that could have been HZ·H ϩ ·(non) 3 , but the intensity was too low for confirmation. Unfortunately, an ion-molecule complex with four ketones exceeded the range of the mass spectrometer and necessitated further studies by APCI MS with a mass range to m/z 2000.…”

“…Traditional methods of colorimetry and amperometry [1,2] are limited in convenience of use and in specificity by chemical or physical interferences from ammonia, moisture, and other vapors. A selective, sensitive, and fast method for the quantitative determination of hydrazines has been demonstrated [3,4] through the gas-phase ionization technique of ion mobility spectrometry (IMS). Such favorable performance can be ascribed to the high proton affinities of hydrazines as found also in atmospheric pressure chemical ionization mass spectrometry (APCI-MS).…”

“…Protonated ammonia, hydrazine, and methylhydrazine at trace levels were resolved using IMS through differences in mobility with a drift tube operated at 484 K [3]. Extension of this concept to a hand-held mobility spectrometer, with a drift tube at ambient temperature, lead to unacceptable resolution of the protonated molecules through formation of hydrated cluster ions without distinctive drift times [4].…”