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)