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291.
CE-MS has gained further attention as a multidimensional analytical approach. The number of publications dealing with this technique is still increasing on the level of application as well as method development-oriented approaches. Additionally, 15 reviews were published the last two years focusing on CE-MS. An overview of all papers found to have been published within 2005 and 2006 is given in tabulated form. Additionally, four promising technical trends are chosen to be presented in detail: (i) chip-based CE-MS, (ii) capillary coatings in CE-MS, (iii) new trends in CEC-MS and (iv) the application of 2-D CE-MS. 相似文献
292.
Patrick Hemberger Zeyou Pan Andras Bodi Jeroen A. van Bokhoven Thomas K. Ormond G. Barney Ellison Nadav Genossar Joshua H. Baraban 《Chemphyschem》2020,21(19):2217-2222
Unveiling reaction mechanisms by isomer-selective detection of reactive intermediates requires advanced spectroscopic knowledge. We study the photoionization of fulvenone (c-C5H4=C=O), a reactive ketene species relevant in catalytic pyrolysis of lignin, which was generated by pyrolysis of 2-methoxy acetophenone. The high-resolution threshold photoelectron spectrum (TPES) with vacuum ultraviolet synchrotron radiation revealed well-resolved vibrational transitions, assigned to ring deformation modes of the cyclopentadiene moiety. The adiabatic ionization energy was determined to be 8.25±0.01 eV and is assigned to the 2A2← 1A1 transition. A broad and featureless band arising at 9 eV is associated with the 2B1← 1A1 excitation. A conical intersection is responsible for the ultrafast relaxation of the fulvenone cation from the into the state resulting in a featureless and lifetime broadened band. These insights will increase the detection capabilities for fulvenone and thereby help to elucidate reaction mechanisms in lignin catalytic pyrolysis. 相似文献
293.
Wang T Fekete A Gaspar A Ma J Liang Z Yuan H Zhang L Schmitt-Kopplin P Zhang Y 《Journal of separation science》2011,34(4):422-427
A novel method for the separation and detection of low molecular weight (LMW) acids was developed using monolithic immobilized pH gradient-based capillary isoelectric focusing coupled with mass spectrometry. Two main parameters, focusing conditions and delivery buffer conditions, which might affect separation efficiency, were optimized with the focusing time of 7 min at 350 V/cm and the delivery buffer of 50% (v/v) acetonitrile in 10 mmol/L ammonium formate (pH 3.0). Under these conditions, the linear correlation between the volume of delivery solvent and the pK(a) of the model components was observed. In addition, the separation mechanism of LMW acids was proposed as well. We suppose that this method may provide a useful tool for the characterization of LMW components (e.g. natural organic matter of different origins). 相似文献
294.