TY - JOUR
T1 - Experimental and theoretical investigation into the correlation between mass and ion mobility for choline and other ammonium cations in N2
AU - Kim, Hyungjun
AU - Kim, Hugh I.
AU - Johnson, Paul V.
AU - Beegle, Luther W.
AU - Beauchamp, J. L.
AU - Goddard, William A.
AU - Kanik, Isik
PY - 2008/3/15
Y1 - 2008/3/15
N2 - A number of tertiary amine and quaternary ammonium cations spanning a mass range of 60-146 amu (trimethylamine, tetramethylammonium, trimethylethylaminonium, N,N-dimethylaminoethanol, choline, N,N-dimethylglycine, betaine, acetylcholine, (3-carboxypropyl)trimethylammonium) were investigated using electrospray ionization ion mobility spectrometry. Measured ion mobilities demonstrate a high correlation between mass and mobility in N2. In addition, identical mobilities within experimental uncertainties are observed for structurally dissimilar ions with similar ion masses. For example, dimethylethylammonium (88 amu) cations and protonated N,N-dimethylaminoethanol cations (90 amu) show identical mobilities (1.93 cm2 V-1 s-1) though N,N-dimethylaminoethanol contains a hydroxyl functional group while dimethylethylammonium only contains alkyl groups. Computational analysis was performed using the modified trajectory (TJ) method with nonspherical N2 molecules as the drift gas. The sensitivity of the ammonium cation collision cross sections to the details of the ion-neutral interactions was investigated and compared to other classes of organic molecules (carboxylic acids and abiotic amino acids). The specific charge distribution of the molecular ions in the investigated mass range has an insignificant affect on the collision cross section.
AB - A number of tertiary amine and quaternary ammonium cations spanning a mass range of 60-146 amu (trimethylamine, tetramethylammonium, trimethylethylaminonium, N,N-dimethylaminoethanol, choline, N,N-dimethylglycine, betaine, acetylcholine, (3-carboxypropyl)trimethylammonium) were investigated using electrospray ionization ion mobility spectrometry. Measured ion mobilities demonstrate a high correlation between mass and mobility in N2. In addition, identical mobilities within experimental uncertainties are observed for structurally dissimilar ions with similar ion masses. For example, dimethylethylammonium (88 amu) cations and protonated N,N-dimethylaminoethanol cations (90 amu) show identical mobilities (1.93 cm2 V-1 s-1) though N,N-dimethylaminoethanol contains a hydroxyl functional group while dimethylethylammonium only contains alkyl groups. Computational analysis was performed using the modified trajectory (TJ) method with nonspherical N2 molecules as the drift gas. The sensitivity of the ammonium cation collision cross sections to the details of the ion-neutral interactions was investigated and compared to other classes of organic molecules (carboxylic acids and abiotic amino acids). The specific charge distribution of the molecular ions in the investigated mass range has an insignificant affect on the collision cross section.
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U2 - 10.1021/ac701888e
DO - 10.1021/ac701888e
M3 - Article
C2 - 18278882
AN - SCOPUS:41449111222
VL - 80
SP - 1928
EP - 1936
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 6
ER -