Multidimensional chromatography The peak kapacity (z * y) if selectivity is different in the columns. Multidimensional chromatography with heart cut Only few bandes are cut. Advantages of multidimensional chromatography Deans switch The flow of mobile phase does not disturb by cut. No moving part are in the hot region. Deans switch Deans switches No reactive surface in the flow pass. The advantage of Deans switch in trace analysis The sample focus in modulator The sample is stopped (frozen) and focused in the modulator. The heating process is very fast. Coeluted peak separation in second dimension in GC xGC The second column is very short . Elution time on it is equal with the collection time of next fraction. Analysis of chlorinated pesticides with GC x GC Analysis of gasoline with GC x GC The first dimension is boiling point selective. Second dimension Π-Π interaction (aromatic) selective. HPLC frequently use off-line technique Horváth Krisztián The concentration of fraction, and the changing of mobile phase is easy with off-line. On-line coupling in HPLC Collection from first column Horváth Krisztián Transpher to second column Ortogonality Same selectivitya Different selectivity Different selectivity Different pH Different stationary phase The anlysis is orthogonal, if their selectivity are based on different interactions Horváth Krisztián Corn oil 2D-HPLC Horváth Krisztián HPLC/GC coupling HPLC/GC coupling HPLC X HPLC On-line coupling of chromatography structure determination methods • GC/MS, GC/FTIR • HPLC/MS, HPLC/MS-MS, HPLC/FTIR, HPLC/NMR • CE/MS, CE/MS-MS On-line LC/MS coupling Magnetic sector mass spectometer S ca n B The bigger mass gives longer pass. Bigger charge give shorter pass. Everday practice the magnetic field is changed, to detect the ions in one point. Sheme of Quadrupol mass spectrometer Sheme of Quadrupol mass spectrometer Used ionization modes Electron impact ionzation (EI) Generally the fragmentation energy is 70 eV. Fragmentation of EI Quality measure is the (m/z) value. The quality measure the heigh of signals. The peak heigh is normalized for biggest peak (base peak, 100%). Certain compound has same fragmentation profile indepently from chromatographic. The quantitation is based on the area of total ion chromatogram (TIC) , or area of selected ions (SIM) Ilustration of fragmentation The moleculs can be puzzle from fragmentogram. Fragmentation The fragmentation is depend on the structure of analyte and fragmentation energy. Chemical ionization CI 1 Torr 10-6 Torr Chemical ionization (CI) • • • • • • • • Pozitív (PCI) NH3 + e -> NH4+ + 2 eNH 4+ + M > NH3 + [M+H] + NH 4 + + M > [M + NH4] + Negatív (NCI) NH3 - e -> NH2NH 2- + M > NH2 + [M+H] NH 2 + + M > [M + NH2] - The pressure of CI is approximatelly 1 Torr. The reagents offer high and selective ionization . The CI is soft ionization having low fragmentation. GC-MS analysis with negative CI Sensitivity has increased with electron capturing heptabutyrofluorid butane derivatives (HFBA) PCI vs. NCI Comparison of various ionization modes GC/MS on-line coupling Izotopselective GC/MS LC/MS couplings The mobile phase has to be totally evaporatable. HPLC/MS electrospray ionization HPLC/MS electrospray ionization HPLC/MS with atmospheric pressure electrospray ionization MS-MS coupling Fast, selective analyses with LC/MS-MS It is not necessary to separate compound, if they hace different fragmentation. Determination of herbicides with LC/MS-MS Ion trap MS The ions are collected in parking circle. Total ion chromatogram (TIC) and selected ion monitoring (SIM) The SIM is more sensitive than TIC with several magnitude. Comparison of TIC and (SIM)