@article{VillatoroZuehlkeRiebeetal.2016,
  author    = {Villatoro, Jos{\´e} Andr{\´e}s and Z{\"u}hlke, Martin and Riebe, Daniel and Riedel, Jens and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd},
  title     = {IR-MALDI ion mobility spectrometry},
  series = {Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry and Analusis},
  volume    = {408},
  journal   = {Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry and Analusis},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1618-2642},
  doi       = {10.1007/s00216-016-9739-x},
  pages     = {6259 -- 6268},
  year      = {2016},
  abstract  = {The novel combination of infrared matrix-assisted laser dispersion and ionization (IR-MALDI) with ion mobility (IM) spectrometry makes it possible to investigate biomolecules in their natural environment, liquid water. As an alternative to an ESI source, the IR-MALDI source was implemented in an in-house-developed ion mobility (IM) spectrometer. The release of ions directly from an aqueous solution is based on a phase explosion, induced by the absorption of an IR laser pulse (lambda = 2.94 mu m, 6 ns pulse width), which disperses the liquid as nano- and micro-droplets. The prerequisites for the application of IR-MALDI-IM spectrometry as an analytical method are narrow analyte ion signal peaks for a high spectrometer resolution. This can only be achieved by improving the desolvation of ions. One way to full desolvation is to give the cluster ions sufficient time to desolvate. Two methods for achieving this are studied: the implementation of an additional drift tube, as in ESI-IM-spectrometry, and the delayed extraction of the ions. As a result of this optimization procedure, limits of detection between 5 nM and 2.5 mu M as well as linear dynamic ranges of 2-3 orders of magnitude were obtained for a number of substances. The ability of this method to analyze simple mixtures is illustrated by the separation of two different surfactant mixtures.},
  language  = {en}
}
@article{VillatoroZuehlkeRiebeetal.2016,
  author    = {Villatoro, Jos{\´e} Andr{\´e}s and Z{\"u}hlke, Martin and Riebe, Daniel and Beitz, Toralf and Weber, Marcus and Riedel, Jens and L{\"o}hmannsr{\"o}ben, Hans-Gerd},
  title     = {IR-MALDI ion mobility spectrometry: physical source characterization and application as HPLC detector},
  series = {International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry},
  volume    = {19},
  journal   = {International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1435-6163},
  doi       = {10.1007/s12127-016-0208-1},
  pages     = {197 -- 207},
  year      = {2016},
  abstract  = {Infrared matrix-assisted laser dispersion and ionization (IR-MALDI) in combination with ion mobility (IM) spectrometry enables the direct analysis of biomolecules in aqueous solution. The release of ions directly from an aqueous solution is based on a phase explosion, induced by the absorption of an IR laser pulse, which disperses the liquid as vapor, nano-and micro-droplets. The ionization process is characterized initially by a broad spatial distribution of the ions, which is a result of complex fluid dynamics and desolvation kinetics. These processes have a profound effect on the shape and width of the peaks in the IM spectra. In this work, the transport of ions by the phase explosion-induced shockwave could be studied independently from the transport by the electric field. The shockwave-induced mean velocities of the ions at different time scales were determined through IM spectrometry and shadowgraphy. The results show a deceleration of the ions from 118 m.s(-1) at a distance of 400 mu m from the liquid surface to 7.1 m.s(-1) at a distance of 10 mm, which is caused by a pile-up effect. Furthermore, the desolvation kinetics were investigated and a first-order desolvation constant of 325 +/- 50 s(-1) was obtained. In the second part, the IR-MALDI-IM spectrometer is used as an HPLC detector for the two-dimensional separation of a pesticide mixture.},
  language  = {en}
}