multidimensional chromatography

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

The concentration of fraction, and the changing of mobile phase is easy with off-line.

Horváth Krisztián

On-line coupling in HPLC

Collection from first column Transpher to second column

Horváth Krisztián

Ortogonality

The anlysis is orthogonal, if their selectivity are based on different interactions

Same selectivitya Different selectivity Different selectivityDifferent pH Different stationary phase

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

Scan B

Magnetic sector mass spectometer

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 e- • NH 4

+ + M > NH3 + [M+H] +

• NH 4 + + M > [M + NH4] +

• Negatív (NCI)• NH3 - e -> NH2

- • NH 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)