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The Principles and Applications of Liquid Chromatography–Mass Spectrometry (LC-MS
- 1. The principle and performance of liquid chromatography–mass spectrometry (LC-MS)
- 2. Liquid chromatography–mass spectrometry (LC-MS) • an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (LC) with the mass analysis capabilities of mass spectrometry (MS) • introduced in 1980s • many compounds can be measured in a single analytical run • very high sensitive and selective • useful in many applications
- 4. Liquid chromatography a) solvent inlet filter, (b) pump, (c) inline solvent filter, (d) injection valve, (e) precolumn filter, (f) column, (g) detector, (h) recorder, (i) backpressure regulator, (j) waste reservoir
- 6. Mass Spectrometry Sample Injection Unit Ionization Source Mass Analyzer Detector System Data System Ion generation Data analyzing Ions sorting by mass (m/z) Detection • Solid • Liquid • Vapor
- 7. Ionization and Interface Electrospray Ionisation (ESI) Atmospheric Pressure Chemical Ionisation (APCI). Atmospheric Pressure Photo-ionisation (APPI) Thermospray Ionisation (TSI) Particle Beam Ionisation (PBI)
- 9. Ionization and Interface Atmospheric Pressure Photo-ionisation Atmospheric Pressure Chemical Ionisation (APCI)
- 11. Ionization and Interface Particle Beam Ionisation (PBI)
- 12. Mass Analyzers • A component of the mass spectrometer • takes and separates ionized masses based on charge to mass ratios • outputs them to the detector where they are detected and later converted to a digital output. Quadrupole Analyzer Time of Flight Analyzer Ion trap Analyzer Hybrid Analyzers
- 14. Time of Flight Analyzer Ion Trap Analyzer Mass Analysers
- 15. • The ions - electrically detected by detector (have been separated according to their mass/charge ratio) • The choice of detector is based on: • the required detection sensitivity and the speed • the thermal and chemical stability Detectors Least sensitive Faraday Cup detector 1000x greater sensitivity compared to Faraday cup Photomultiplier detector Most sensitive. Used for high resolution Photographic detector
- 19. Data Recording Capturing a complete mass spectrum - SCAN technique Selected ion monitoring - SIM technique Selected ion monitoring - SIM technique
- 20. Applications Pharmaceutical analysis Bioavailability studies Drug degradation product analysis Screening and Characterization of potential drugs Drug metabolism studies, pharmacokinetic s Identifying of drug targets Biomolecule characterization Proteins and peptides Oligonucleotides Forensic analysis Environmental analysis Pesticides on foods Soil and groundwater contamination
Editor's Notes
- ESI operates according to the following scheme: 1) the column effluent from the LC containing analytes is pumped through a capillary which is held at high potential (2-6 kV) and nebulized. The applied voltage can be either positive or negative, depending on the analytes; nebulization is usually assisted pneumatically (except in nanospray); 2) the droplets that detach from a tip of the capillary contain an excess of positive or negative charge as a result of the applied high voltage; 3) electrical field gradient attracts charged droplets towards the entrance of the mass spectrometer; 4) charged analyte molecules are generated from the small charged droplets either by the charged residue model or by the ion evaporation model. Ion formation from the droplets is promoted by a flow of drying gas (usually heated nitrogen); 5) the ions, solvent vapor and drying gas molecules are sampled through a capillary into a first pumping stage (0.08-0.75 Torr) where they are supersonically expanded; 6) the ions and some other neutral molecules are sampled via a skimmer into the second pumping stage (0.001-0.01 Torr) containing an ion focusing and transfer device (usually RF hexapole or octapole and a set of lenses); 7) ions enter mass analyzer region (< 10-5 Torr).
- ESI operates according to the following scheme: 1) the column effluent from the LC containing analytes is pumped through a capillary which is held at high potential (2-6 kV) and nebulized. The applied voltage can be either positive or negative, depending on the analytes; nebulization is usually assisted pneumatically (except in nanospray); 2) the droplets that detach from a tip of the capillary contain an excess of positive or negative charge as a result of the applied high voltage; 3) electrical field gradient attracts charged droplets towards the entrance of the mass spectrometer; 4) charged analyte molecules are generated from the small charged droplets either by the charged residue model or by the ion evaporation model. Ion formation from the droplets is promoted by a flow of drying gas (usually heated nitrogen); 5) the ions, solvent vapor and drying gas molecules are sampled through a capillary into a first pumping stage (0.08-0.75 Torr) where they are supersonically expanded; 6) the ions and some other neutral molecules are sampled via a skimmer into the second pumping stage (0.001-0.01 Torr) containing an ion focusing and transfer device (usually RF hexapole or octapole and a set of lenses); 7) ions enter mass analyzer region (< 10-5 Torr).