TY  - JOUR
A1  - Zühlke, Martin
A1  - Riebe, Daniel
A1  - Beitz, Toralf
A1  - Löhmannsröben, Hans-Gerd
A1  - Zenichowski, Karl
A1  - Diener, Marc
A1  - Linscheid, Michael W.
T1  - An electrospray ionization-ion mobility spectrometer as detector for high-performance liquid chromatography
JF  - European journal of mass spectrometry
N2  - The application of electrospray ionization (ESI) ion mobility (IM) spectrometry on the detection end of a high-performance liquid chromatograph has been a subject of study for some time. So far, this method has been limited to low flow rates or has required splitting of the liquid flow. This work presents a novel concept of an ESI source facilitating the stable operation of the spectrometer at flow rates between 10 mu L min(-1) and 1500 mu L min(-1) without flow splitting, advancing the T-cylinder design developed by Kurnin and co-workers. Flow rates eight times faster than previously reported were achieved because of a more efficient dispersion of the liquid at increased electrospray voltages combined with nebulization by a sheath gas. Imaging revealed the spray operation to be in a rotationally symmetric multijet-mode. The novel ESI-IM spectrometer tolerates high water contents (<= 90%) and electrolyte concentrations up to 10 mM, meeting another condition required of high-performance liquid chromatography (HPLC) detectors. Limits of detection of 50 nM for promazine in the positive mode and 1 mu M for 1,3-dinitrobenzene in the negative mode were established. Three mixtures of reduced complexity (five surfactants, four neuroleptics, and two isomers) were separated in the millisecond regime in stand-alone operation of the spectrometer. Separations of two more complex mixtures (five neuroleptics and 13 pesticides) demonstrate the application of the spectrometer as an HPLC detector. The examples illustrate the advantages of the spectrometer over the established diode array detector, in terms of additional IM separation of substances not fully separated in the retention time domain as well as identification of substances based on their characteristic IMs.
KW  - ESI
KW  - IMS
KW  - HPLC
KW  - spray imaging
KW  - neuroleptics
KW  - pesticides
KW  - surfactants
Y1  - 2015
U6  - https://doi.org/10.1255/ejms.1367
SN  - 1469-0667
SN  - 1751-6838
VL  - 21
IS  - 3
SP  - 391
EP  - 402
PB  - WeltTrends
CY  - Sussex
ER  - 
TY  - JOUR
A1  - Zühlke, Martin
A1  - Riebe, Daniel
A1  - Beitz, Toralf
A1  - Löhmannsröben, Hans-Gerd
A1  - Andreotti, Sandro
A1  - Reinert, Knut
A1  - Zenichowski, Karl
A1  - Diener, Marc
T1  - High-performance liquid chromatography with electrospray ionization ion mobility spectrometry: Characterization, data management, and applications
JF  - Journal of separation science
N2  - The combination of high-performance liquid chromatography and electrospray ionization ion mobility spectrometry facilitates the two-dimensional separation of complex mixtures in the retention and drift time plane. The ion mobility spectrometer presented here was optimized for flow rates customarily used in high-performance liquid chromatography between 100 and 1500 mu L/min. The characterization of the system with respect to such parameters as the peak capacity of each time dimension and of the 2D spectrum was carried out based on a separation of a pesticide mixture containing 24 substances. While the total ion current chromatogram is coarsely resolved, exhibiting coelutions for a number of compounds, all substances can be separately detected in the 2D plane due to the orthogonality of the separations in retention and drift dimensions. Another major advantage of the ion mobility detector is the identification of substances based on their characteristic mobilities. Electrospray ionization allows the detection of substances lacking a chromophore. As an example, the separation of a mixture of 18 amino acids is presented. A software built upon the free mass spectrometry package OpenMS was developed for processing the extensive 2D data. The different processing steps are implemented as separate modules which can be arranged in a graphic workflow facilitating automated processing of data.
KW  - Amino acids
KW  - Electrospray ionization
KW  - Ion mobility spectrometry
KW  - Pesticides
KW  - Two-dimensional separations
Y1  - 2016
U6  - https://doi.org/10.1002/jssc.201600749
SN  - 1615-9306
SN  - 1615-9314
VL  - 39
SP  - 4756
EP  - 4764
PB  - Wiley-VCH
CY  - Weinheim
ER  -