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FD) and Liquid Injection Field Desorption Ionization (LIFDI Soft ionization by Field Ionization (FI), Field desorption (FD) and Liquid Injection Field Desorption Ionization (LIFDI) H. Bernhard Linden Linden CMS GmbH [email protected] www.LIFDI.com 1 LINDEN CMS GmbH, 2012 Soft ionization by FI, FD and LIFDI Introduction by mouth watering soft ionization spectra 1. General and theoretical overview 2. Various instruments – identical technique 3. Automated LIFDI 4. Improved FI intensity 5. LIFDI on FT-ICR instruments 6. LIFDI of air/moisture sensitive metal complexes 7. Orbitrap with ESI-LIFDI combination 2 LINDEN CMS GmbH, 2012 FI and FD are known for soft ionization of non-polar compounds, LIFDI outperforms other MS techniques for characterization of organometallics due to its softness and convenient handling order of soft ionization References Liquid injection field desorption/ionization of transition decomposition decreases : ESI > LIFDI metal fluoride complexes Trevor A. Dransfield, Ruqia Nazir, Robin N. Perutz and “LIFDI ... gave the molecular ion peaks [M]+ as base peaks (100%) ... Adrian C. Whitwood With ESI, the compounds showed decomposition.” J. Fluorine Chem. 131, 2010, 1213-1217 loss of CO decreases : MALDI > FAB > FD *) Analysis of ruthenium carbonyl–porphyrin complexes: a comparison of matrix-assisted laser desorption/ionisation “ruthenium carbonyl complexes exhibited time-of-flight, fast-atom bombardment and field desorption abundant carbon monoxide (CO) loss in MALDI-TOF-MS and still a mass spectrometry, measurable CO loss in FAB-MS. Only FD-MS yielded the molecular ion M. Frauenkron, A. Berkessel and J. H. Gross as the base peak of the spectra in all cases.” Eur. J. Mass Spectrom. 1997, 3, 427 - 438 “fragmentation decreases Comparison of electrospray mass spectrometry with other soft ionization techniques for the characterization of cationic along the series FAB > ESI > FD “ *) π-hydrocarbon organometallic complexes , L. A. P. Kane-Maguire, R. Kanitz and M. M. Sheil J. Organometallic Chem., 1995, 486, 1-2, 243-248 *) Note: LIFDI wasn’t invented in the 90-ies yet, but LIFDI and FD share the same soft ionization, only the sample supply is different. 3 LINDEN CMS GmbH, 2012 example for soft ionization Mo(CO)4(Sb4Et4Pr2) sample of H.J. Breunig, University Bremen, Germany Et Et m/z = 897,8 Pr Sb assumed formula and structure Sb expected Mo(CO) 4 isotope pattern Sb Pr Sb oily, very reactive matter Et Et • decomposition upon chromatography • no crystals for X-ray characterization • ambiguous NMR data • elemental analysis not confirming the MW all routinely used • ESI - ineffectual due to dry toluene as solvent techniques failed • MALDI - rather impossible under inert conditions • EI did not show meaningfull spectra 4 LINDEN CMS GmbH, 2012 the presence of a mixture with scrambling alkyl ligands caused the oily consistence + Mo(CO) [(Sb Et Pr )] elucidating why X-ray, NMR 4 4 (6-n) n and elemental analysis failed reactive, air sensitive oil with 1 ≤ n ≤ 6 Et Et Pr Sb LIFDI showed the Sb note: loss of ligands does not occur at least expected + Mo(CO)4 not from M (n=2) isotope pattern Sb for n=1-6 no (n=2) Pr Sb loss of Et CO from Et no (n=2) loss of Et from (n=2) no (n=4) loss of Pr from (n=1) (n=3) (n=2) (n=6) (n=5) Liquid Injection Field Desorption Ionization Mass Spectrometry of Cyclic Metal Carbonyl Complexes with Tetra-Antimony Ligands H. J. Breunig, H. B. Linden, O. Moldovan J. Am. Soc. Mass Spectrom., 2013, 24, 164-166 5 LINDEN CMS GmbH, 2012 X-ray data showed clearly all Ga atoms and C60H90Ni7Ga 6 all Cp* ligands but the Ni atoms were initially ambiguous due to the impurity with 8 Ni atoms. + [Ni78(GaCp*)(GaCp*)6] Single-crystal X-ray crystallography instrument: Waters LCT, Ruhr University Bochum, Germany sample: courtesy Prof. Dr. Roland A. Fischer, Ruhr University Bochum, Germany LINDEN CMS GmbH 6 One of the reviewers C64H88N4Cr2 suggested the above structure and refused accepting the publication [{({iPr2(C6H3)}2nacnac)Cr}2(m-Ph)(m-H)] unless proving the presence of the hydride ligand of the lower structure + M by a shift of the mole peak upon H/D exchange by just 1 Da (mole peak intensities of 5% would be sufficient) isotope pattern calculated measured A Tale of Two Isomers: A Stable Phenyl Hydride and a High-Spin (S=3) Benzene Complex of Chromium WH Monillas, GPA Yap, and KH Theopold, Angew. Chem. Int. Ed. 2007, 46, 6692-6694 instrument: Waters GCT, industrial R&D lab, Ludwigshafen, Germany LINDEN CMS GmbH 7 LIFDI of Grubbs Hoveyda Catalyst M+ C31H38Cl2N2ORu m/z 626.1405 calculated isotope pattern measured isotope pattern 548,12 + (M-C3H7Cl) -HCl instrument: Waters Q-TOF II, Humboldt University, Berlin, Germany LINDEN CMS GmbH 8 Broadband LIFDI-FT-ICR mass spectrum of polystyrene 1050 M+• peaks n n=6 n=14 9 instrument: Bruker Apex with LIFDI-ESI combination source, University Heidelberg, Germany LINDEN CMS GmbH, 2012 Diesel eicosane nonadecane heptadecane heneicosane tricosane tetradecane tetracosane undecane heptacosane instrument: Thermo Fisher MAT900, University of Vienna, Austria 10 LINDEN CMS GmbH, 2012 LIFDI of liquid Si 69 TIC at 12 kV: -5 bis-(3-triethoxysilylpropyl)polysulfide above 10 A “organosilane coupling agent for production of silica reinforced rubber ” 11 LINDEN CMS GmbH, 2000 Bis(3-triethoxysilylpropyl)disulphide M+ 163 237 429 H5C2 — O O — C2 H5 H5C2 — O — Si — (CH2)3 — S — S — (CH2)3 — Si — O — C2 H5 H5C2 — O O — C2 H5 237 instrument: MAT 95 sample: industrial R&D lab, Hanau, Germany 12 LINDEN CMS GmbH, 2006 doubly charged ions KH Gunzelmann, HM Hutmacher, R Wolf, J Richert, BASF AG, German MS meeting 2005 Sample: Z. Tomovic, M. D. Watson, K. Müllen, Angew. Chem. Int. Ed. 2004, 43, 755-758 13 LINDEN CMS GmbH, 2006 Soft ionization by FI, FD and LIFDI Introduction 1. General and theoretical overview 2. Various instruments – identical handling 3. Automated LIFDI 4. Improved FI intensity 5. LIFDI on FT-ICR instruments 6. LIFDI of air/moisture sensitive metal complexes 7. Orbitrap with ESI-LIFDI combination 14 LINDEN CMS GmbH, 2012 FI, FD and LIFDI share the soft ionization mechanism but differ in Fieldterms of Ionization analyte and sample supply IUPAC : „removal of electrons from any species acronym full name type of analyte and sample supply by interaction with a high electrical field “ IUPAC 12.3.1. Ionization nomenclature 1997 FI i ntroduced : FeldemissionField Ionization, E.W. Müller, Ergebnisse der exakten analyte, Naturwissenschaften , 27, 1953, 290 -360 on p. 359 in chapter “Other applications of the field electron microscope” continuously supplied via gas inlet e.g. GC Mass Spectrometric Analysis of Ions from the Field Microscope, M.G . Inghram and R. Gomer, J. Chem. Phys., 22, 1954, 1279-80 vaccuum lock FD Field Desorption dissolved solid analyte, discontinuously loaded to emitter surface of vacuum Field Desortion Mass Spectrometry: a Technique for the Study of Thermally Unstable Substances of Low Volatility, H.D . Beckey , Int.J.Mass Spectrom. Ion Phys., 2, 1969, 500-503 LIFDI Liquid Injection , liquid or dissolved solid analyte, vaccuum lock Field Desorption supplied through capillary Ionization of vacuum discontinuously or continuously Liquid Injection Field Desorption Ionization: a New Tool for Soft Ionization of Samples Including Air-Sensitive Catalysts and Non-Polar Hydrocarbons, H.B. Linden, Eur. J. Mass Spectrom. 10, 2004, 459-468 15 LINDEN CMS GmbH, 2012 FI/FD/LIFDI emitter Beckey, H.D.; Hilt, E.; Schulten, H.R. High Temperature Activation of Emitters for Field Ionization and Field Desorption Spectrometry, J. Phys. E:Sci. Instrum. 1973, 6, 1043-1044 Linden, H.B.; Hilt, E.; Beckey, H.D. High-Rate Growth of Dendrites on Thin Wire Anodes for Field Desorption Mass Spectrometry, J. Phys. E:Sci. Instrum. 1978, 11, 1033-1036 Rabrenovic, M.; Ast, T.; Kramer, V. Alternative Organic Substances for Generation of Carbon Emitters for Field Desorption Mass Spectrometry, Int. J. Mass Spectrom. Ion Phys. 1981, 37, 297-307 graphite dendrites have large surface for adsorption of sample 4 and enhance the electrical field strength by a factor 10 16 LINDEN CMS GmbH, 2011 A potential difference of 104 V generates a field strength of several 1010 V/m ● ● (not to scale) ● ● ● 4 ~5 x 10 V/µm whisker tip ● ● ● V F = D ● ● 10 kV V ~5 V/µm * K 2 mm Fo= tip ro K = 2 / ln(2D/r ) tip o with D >> ro ~ 30nm H.D .Beckey,Principles of Field Desorption counter and Field Ionization Mass Spectrometry; Pergamon Press: Oxford, 1977, p.82 electrode 17 LINDEN CMS GmbH, 2012 A potential difference of 104 V generates a field strength of several 1010 V/m δ+ δ- - ● ● ● +• (not to scale) ● ● ● --10 261480 kV ● +20 V ● ● ● ● - ● ● the weakest bound electron ● ● whereas in EI is removed in FI, FD, LIFDI by bymaking 70 eV EI electrons ions with field ionization quantum mechanical tunneling anyinternal inner electron excess making ions without can beenergy removed internalhalf live excess of hydrogen energy ● 1.3x10–1 s at 0.5 *104 V µm–1 –10 4 –1 IE ~ 10 eV 1.6x10 s at 1.0 *10 V µm ● ● 2.0x10–16 s at 2.5 *104 V µm–1 ● ● H.D .Beckey,Principles of Field Desorption 18 IE << 10 eV and Field Ionization Mass Spectrometry; LINDEN CMS GmbH, 2012 Pergamon Press: Oxford, 1977, p.4 FI LIFDI protocol protocol for volatile samples only for volatile and non-volatile, polar and nonpolar, reactive and non-reactive samples insert new emitter, insert new emitter, tune with acetone tune with acetone inert inert flash emitter clean yes conditions heat emitter clean yes conditions (under feed back) required required ? ? no no admit dip LIFDI capillary acquire data acquire data sample gas in sample solution continuously (with EHC ramp) for 1-3 s Coulor code: sample supply (highlighted green), data acquisition (bold blue) and cleaning the emitter (bold brown) Steps with substantial risk to breaking the emitter wire are highlighted bold red.
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