Plasma chromatography with ammonium reactant ions

Kim, S. H.; Karasek, F.W.; Rokushika, Souji

doi:10.1021/ac50023a034

Cited by 39 publications

(25 citation statements)

References 16 publications

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“…Adding trace quantities of vapors to ion mobility spectrometers to produce specific analytical effects was first utilized by Kim et al (1978) who added ammonia to the N 2 carrier gas to selectively ionize a series of amines [1]. Later, Blyth (1983) used acetone for the selective detection of chemical warfare agents [2] and Spangler et al (1985) introduced the use of carbon tetrachloride for the selective detection of explosives [3].…”

Section: Introductionmentioning

confidence: 99%

Using a buffer gas modifier to change separation selectivity in ion mobility spectrometry

Fernandez‐Maestre

Hill

2010

International Journal of Mass Spectrometry

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The mobilities of a set of common α-amino acids, four tetraalkylammonium ions, 2,4-dimethyl pyridine (2,4-lutidine), 2,6-di-tert-butyl pyridine (DTBP), and valinol were determined using electrospray ionization-ion mobility spectrometry-quadrupole mass spectrometry (ESI-IMS-QMS) while introducing 2-butanol into the buffer gas. The mobilities of the test compounds decreased by varying extents with 2-butanol concentration in the mobility spectrometer. When the concentration of 2-butanol increased from 0.0 to 6.8 mmol m −3 (2.5×10 2 ppmv), percentage reductions in mobilities were: 13.6% (serine), 12.2% (threonine), 10.4% (methionine), 10.3% (tyrosine), 9.8% (valinol), 9.2% (phenylalanine), 7.8% (tryptophan), 5.6% (2,4-lutidine), 2.2% (DTBP), 1.0% (tetramethylammonium ion, TMA, and tetraethylammonium ion, TEA), 0.0% (tetrapropylammonium ion, TPA), and 0.3% (tetrabutylammonium ion, TBA). These variations in mobility depended on the size and steric hindrance on the charge of the ions, and were due to formation of large ion-2-butanol clusters. This selective variation in mobilities was applied to the resolution of a mixture of compounds with similar reduced mobilities such as serine and valinol, which overlapped in N 2 -only buffer gas in the IMS spectrum. The relative insensitivity of tetraalkylammonium ions and DTBP to the introduction of 2-butanol into the buffer gas was explained by steric hindrance of the four alkyl substituents in tetraalkylammonium ions and the two tert-butyl groups in DTBP, which shielded the positive charge of the ion from the attachment of 2-butanol molecules. Low buffer gas temperatures (100 °C) produced the largest reductions in mobilities by increasing ion-2-butanol interactions and formation of clusters; high temperatures (250 °C) prevented the formation of clusters, and no reduction in ion mobility was obtained with the introduction of 2-butanol into the buffer gas. Low temperatures and high concentrations of 2-butanol produced a series of ion clusters with one to three 2-butanol molecules in compounds without steric hindrance. Clusters of two and three molecules of 2-butanol were also visible. Ligand-saturation on the positive ions with 2-butanol molecules occurred at high concentrations of modifier (6.8 mmol m −3 at 150°C); when saturated, no further reduction in mobility occurred when 2-butanol was introduced into the buffer gas.

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Section: Introductionmentioning

confidence: 99%

Using a buffer gas modifier to change separation selectivity in ion mobility spectrometry

Fernandez‐Maestre

Hill

2010

International Journal of Mass Spectrometry

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“…For the first time, in 1978, ammonia was added to the carrier gas in the IMS detector to selectively ionize amines [26]. The results of these studies show that ammonia effectively suppressed ionization of interferents from the solvent.…”

Section: Ammoniamentioning

confidence: 99%

“…Therefore, it is necessary to find a solution to minimize the effects of the matrix [26]. The solution to this problem would be to add a small amount of admixture (dopant) into the reaction region at an appropriate concentration [27].…”

Section: Dopants Suppressing the Ionization Of Interferents In The Pomentioning

confidence: 99%

Dopants and gas modifiers in ion mobility spectrometry

Waraksa

Perycz

Namieśnik

et al. 2016

TrAC Trends in Analytical Chemistry

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“…Under the influence of low levels of NH 3 , only very strong gas-phase bases, such as amines and drugs, will respond in the IMS. 5 An example of selective ionization in the negative ion mode is the addition of methylene chloride to enhance the response of electronegative explosives. 6 The methylene chloride produces a negative reactant ion, Cl Ϫ , which selectively attaches to certain explosives, forming a stable adduct product ion.…”

Section: Selectivitymentioning

confidence: 99%