TY - CONF A1 - Michalik-Onichimowska, Aleksandra A1 - Riedel, Jens A1 - Panne, Ulrich T1 - Coupling of Acoustically Levitated Droplets with Ion Mobility Spectrometry T2 - DGMS 2015 N2 - Introduction The list of applications for ion mobility spectrometry (IMS) is steadily growing quickened by advances in instrumental design, experimental methods and accompanying theory. The performance of IMS is greatly influenced by the ionization source and the introduction of the analyte, hence new ionization schemes and sampling strategies recently received particular interest.[1] An overall new approach is the coupling of IMS to an acoustically levitated droplet and combined sample desorption/ionization by a laser. In this setup the acoustically levitated droplet works as a wall-less micro reactor.[2] The latter opens the way towards quality control of fast reactions. Generally, the combination of acoustically levitated droplet and IMS bears a wide range of applications from routine analysis to microfluidic optimization of chemical reactions. Experimental part A novel coupling of an acoustically levitated droplet with a homebuilt drift tube ion mobility spectrometry is presented. A new prototype of inlet was customized according to design constrains yielding in maximum ion transmission. Moreover, the commonly used plate repeller was replaced with a point electrode to form a concentric electric field between the droplet and the IMS, geometrically allowing space for the acoustically levitated droplet. The desorption/ionization out of the droplet was performed with an optical parametric oscillator at 2,94 µm wavelength with pulse duration of FWHM = 7 ns. Primary evaluation of the setup was achieved using tetra-n-butylammonium bromide, promazine, perphenazine and L-arginine in direct comparison with the results obtained with a µdroplet IR-MALDI IMS. Results and discussion The coupling of acoustically levitated droplet with IMS was successfully realized giving further possibilities to utilize it as detection method to interrogate the fast kinetics of reactions preformed directly in the droplet. The presented modifications simplify the assembly of the setup and allow for a sufficient isolation between the high voltage, applied on the individual electrodes of the IMS, and the acoustic field sonotrode. The implemented point electrode produces a concentric steep potential field around the acoustically levitated droplet forcing the flow of nascent ions towards the drift tube inlet region. Additionally, it minimizes spatial restrictions giving space for a better accessibility for the sampling laser beam. The recorded ion mobility spectra confirm that the entire arrangement results in an efficient desorption, ionization and ion transfer of the sample liquid. First results show a sensitivity of the IMS comparable to that of the previously introduced µdroplet IR-MALDI. However the main advantage of acoustically levitated droplet is the reduction of long memory effect typically observed for the µdroplet source. These memory effects are attributed to wash-out times of the sample volume and to contamination of surfaces that get into contact with the sample. The contribution can therefore positively demonstrate that by avoiding sample-surface interfaces, the instrument response function can be drastically shortened. This not only significantly decreases the time necessary to clean the system between subsequent measurements but mostly opens the path towards fast kinetic monitoring of chemical reactions within the microdroplet reactors. New aspects The combination of acoustically levitated droplets and ion mobility separation provides a tool for direct online detection of reaction kinetics. T2 - DGMS 2015 CY - Wuppertal DA - 2015-03-01 PY - 2015 AN - OPUS4-34778 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Michalik-Onichimowska, Aleksandra A1 - Riedel, Jens A1 - Panne, Ulrich A1 - Löhmannsröben, Hans-Gerd A1 - Beitz, Toralf T1 - The effect of laser pulse duration on atmospheric pressure IR-MALDI using liquid matrices T2 - Bunsentagung 2015 N2 - Matrix assisted laser desorption/ionization using liquid matrices and infrared laser irradiation (liquid IR-MALDI) is an attractive detection scheme since it enables a direct coupling to liquid chromatographic separation techniques.1 Albeit extensive studies have been targeted to achieve a more general understanding of the underlying ionization mechanism, the exact role of individual contributions, such as thermal vaporization, phase explosion or photoablation, could not be exhaustively identified.2 This contribution will present a direct comparison of ion mobility (IM) spectra obtained by utilizing an optical parametric oscillator and an Er:YAG laser, both operating at a central wavelength of = 2.94 µm, but with temporal pulse widths of 7 ns or several hundred µs, respectively. Thus, the resulting peak power of the Er:YAG laser is three orders of magnitude smaller than that of the OPO, however supplies a tenfold higher energy per pulse. In addition to the mere detection efficiencies, analysis of the IM spectrometric results gives insights into the initial solvation state of the formed ions. Accompanying high speed shadowgraphy imaging experiments contribute towards a better understanding of the involved liquid-gas phase transition dynamics. T2 - Bunsentagung 2015 CY - Bochum DA - 2015-05-14 PY - 2015 AN - OPUS4-34777 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Michalik-Onichimowska, Aleksandra A1 - Riedel, Jens A1 - Panne, Ulrich A1 - Löhmannsröben, H.-G. T1 - Real time monitoring of photoreactions performed within levitated droplets by LA-DBD-MS N2 - The upscaling from small scale academic reactors to large industrial processes typically suffers from a large change in surface-to-volume ratio. A promising approach is the general avoidance of surfaces as in levitated droplet techniques. However, up to now, no mass spectrometric interface for online reaction monitoring in levitated droplets has been provided. As model reaction the photoinitiated thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was studied. A droplet of 5 µL reactand solution was provisioned into an acoustic trap aligned lateral to the MS inlet. Contactless sampling by laser ablation (LA) is followed by dielectric barrier discharge (DBD) postionization. The latter is needed to address non polar reaction partners. T2 - 21st International Mass Spectrometry Conference CY - Toronto, Canada DA - 20.08.2016 KW - Monitoring of chemical reactions KW - Acoustic levitation KW - Laser ablation KW - Mass spectrometry PY - 2016 AN - OPUS4-37159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Michalik-Onichimowska, Aleksandra A1 - Riedel, Jens A1 - Panne, Ulrich T1 - Monitoring of Thiol-Ene Coupling by Mass Spectrometry and Ion Mobility Spectrometry T2 - ESCRE 2015 N2 - The carbon-sulfur bond is frequently occurring in natural products and pharmaceuticals. In a wide range of industrial applications such as polymers and bioorganic functionalization, biomaterials and nanostructured networks formation and microdevice fabrication the targeted construction of C-S bonds is being synthetically important. The synthesis of thioethers is mainly conducted by radical thiol-ene click reactions typically initiated by thermal or UV activation of a radical initiator or direct radical formation via UV irradiation. The reported conversion yields are high after relatively short irradiation times, thus, a fast reaction monitoring is necessary to optimize reaction conditions in terms of total yield and occurrence of undesired by-products. Especially for fast reactions, rapid response is the key feature for online monitoring. The latter gets increasingly important in process analytical approaches for quality assurance and to better control the conversion rate by feedback control. For a headspace analysis, gas detection methods like ion mobility spectrometry (IMS) and mass spectrometry (MS) are especially suitable to this aim since they provide response times in the ms - s range. Moreover, as complementary methods they provide comprehensive information about the molecule and it's structure. The aim of the work is to qualitatively interrogate the sample composition of a photocatalytically initiated thiol-ene coupling in real time. This contribution presents primary results of direct analysis of the photoinitiated synthesis of methyl 2-((tert-butoxycarbonyl)amino)-3-((3-hydroxypropyl)thio) propanoate by IMS and MS utilizing different ionization sources. The thiol-ene reaction is performed between N-Boc-cysteine methyl ester and allyl alcohol utilizing Ru(bpz)3(PF6)2 catalyst as a photoinitiator and p-toluidine as a redox mediator, irradiated at 450 nm according to the procedure presented in [2]. The obtained results were validated by NMR analysis unambiguously indicating the formation of the newly formed C-S bond and additionally providing total reaction yield calibration curves for a quantitative analysis. T2 - ESCRE 2015 CY - München DA - 2015-10-27 PY - 2015 AN - OPUS4-34779 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -