Mobilidade ionica acoplada a espectrometria de massas : interferencia de parametros do drift gas na resolução de anilinas substituidas e determinação da mobilidade intrinsica de agregados de liquidos ionicos / Ion mobility mass spectrometry : interference of drift gas parameters on the resolution of substituted anilines and determination of intrinsic mobility of ionic liquids aggregates

AUTOR(ES)

Priscila Micaroni Lalli

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

24/02/2010

RESUMO

Ion mobility spectrometry separates ions with different sizes or spacial conformations in gas phase according to the time they take to travel through a gas under the influence of an electrical field. Coupling this technique to mass spectrometry provides an extremely versatile tool, able to investigate molecular structure and separate complex samples, including isomers. In Chapter I, different gases were used to separate the isomers N-butyl aniline and p-butil aniline in order to investigate the ion/molecule interaction during the ion mobility process. We have shown that drift gas molecules don¿t act only as physical barriers that slow down the ions, as they are usually considered, but they may interact chemically with them. In the case of these isomers, more polarizable gases such as ethene and CO2 have shown to improve considerably the isomer separation. We believe that the large difference of polarizability between both isomers is related to this fact, because more polarizable gases would interact better with the more polarizable isomer slowing it down more intensively. More massive gases and higher pressures also help improve isomer separation. In Chapter II, IMMS was used to perform the first measurements of the intrinsic mobility of a series of gaseous cationic and anionic aggregates of ionic liquids. Results confirm previous mobility measurements by NMR, which show an apparent anomaly in which the bulkier cations travel faster than respective anions. This behavior isn¿t well understood yet, however, it may be related to the ions orientation by the field or to the hardness difference between cations and anions.

ASSUNTO(S)

espectrometria de massa mobilidade ionica isomeros liquidos ionicos mass spectrometry ion mobility isomers ionic liquids

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