GC-MS combines gas chromatography and mass spectrometry to separate and identify compounds in a sample. It works by vaporizing the sample, separating the compounds via gas chromatography, and then using mass spectrometry to determine the mass-to-charge ratios which can be used to identify the compounds. LC-MS is similar but uses liquid chromatography instead of gas chromatography to first separate compounds based on their polarity before entering the mass spectrometer. Both techniques are highly sensitive and useful for applications like drug detection, environmental analysis, and metabolomics. Hyphenated techniques provide the advantages of both separation and identification capabilities in a single analysis.
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2. Contents
1. Introduction
2. List of Hyphenated Techniques
3. GC-MS
4. LC-MS
5. GC-IR
6. LC-ESI-MS
7. Advantages of Hyphenated Techniques
8. References
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3. What Is Hyphenated Technique ?(1)
The term hyphenation was first adapted by Hirschfeld in
1980.
The technique developed from the coupling of a separation
technique and an on-line spectroscopic detection technology
is known as hyphenated technique.
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Introduction
4. Hyphenated techniques ranges from
combination of
1. Separation-separation
2. Separation-identification &
3. Identification- identification techniques
Introduction 界看稼岳庄.
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7. Principles :
GC :
May be Gas Liquid [GLC] or Gas Solid Chromatography [GSC]
but GLC is preferred
GLC works by partition but GSC works by adsorption
In GLC the substance to be studied first converted to gas which
works as the mobile phase.
MS :
1. Ion Formation
2. Ion Separation & Detection 7
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8. Techniques used to form ions are:
1. Electron Ionisation
2. Chemical Ionisation
3. Desorption Ionisation
i. Secondary Ion Mass Spectroscopy [SIMS]
ii. Fast Atom Bombardment [FAB]
iii. Matrix Associated Laser Desorption
Ionisation [MALDI]
4. Electrospray Ionisation
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1. Ion Formation
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9. 2. Ion Separation and Detection
Types of instruments are used:
i. Direct Focusing Type:
a) Single Focusing
b) Double Focusing
ii. Quadruple Mass Analyser
iii. Quadruple Mass Storage
iv. Time of Flight Mass Analyser
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10. Instrumentation of GC :
A. Carrier Gas:
Chemically inert
Suitable for the detector use
Amount of impurity should be less
Easily available and should be cheap
Non inflammable
Generally used carrier gases are
He, H, N, Ar etc.
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11. B. Flow Regulators:
Used to maintain the
uniform pressure and
flow rate.
Generally used are:
Rotameter
Soap Bubble Flow Meter
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12. C. Injection Devices:
GAS : Valve Devices
LIQUID : Loop Devices
SOLID : Dissolve the
substance in suitable
solvent and then inject.
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13. D. Columns:
Columns can be of the following types:
Packed Columns [Stationary Phase- PEG]
Open Tubular Column or Open Capillary Column/ GOLAY Column
SCOT ( Support Coated Open Tubular Column)
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14. E. Temperature Controlling Devices:
The devices are very important role playing.
Generally used Temperature Controlling Devices are:
Pre heaters(for vapour formation)
Thermostatically controlled oven
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16. Principle of working and interfaces :
GC-MS works by :
1. Iso Thermal Principle
2. Liner Principle
Interfaces of GC MS are :
1. Molecular Separator
2. Permeation Separator
3. Open Split
4. Capillary Direct
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18. Gather Evidence
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Police Officer
1. Interview witness
2. Dust for fingerprints
Mass Spectrometrist
1. Interview biologists who
isolated the protein
2. Cleave protein to obtain
peptide mixture
3. Analyse peptide mixture by MS
to obtain Peptide molecular
masses !
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19. 19
Database Search Results
Police Officer
Identifies the robber
Mr. XYZ
Mass Spectrometrist
Identifies the protein
e.g. bovine carbonic
anhydrase
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20. Applications of GC-MS :(1)
Elucidation of the structure of organic & biological
molecules.
Impurity profiling of pharmaceuticals.
Identification of components in thin layer & paper
chromatograms.
Identification of drugs of abuse & metabolites of drugs of
abuse in blood, urine & saliva.
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GC-MS 界看稼岳庄.
21. Sports antidoping analysis (in forensic GC-MS).
Analyzer of aerosol particles.
Determination of pesticide residues in food.
Polymer characterization (pyrolysis methods combined
GCMS).
Drug monitoring & toxicology studies.
Explosive analysis
Environmental analysis
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35. Detectors :
Records either the charge induced or the current produced
when an ion passes by or hits a surface.
A continuous dynode particle
multiplier detector
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39. Pharmacokinetics: Bio analysis
Drug development
Molecular weight determination
Toxicology
Impurity detection
Determination of isotopes
Proteomics/Metabolomics
Determination of pesticides, herbicides & organic
pollutants for environmental ,monitoring.
Applications of LC-MS :(1)
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40. Comparison of LC-MS with GC-MS :
GC-MS requires compounds to be volatile to be ionised.
- traditionally electron impact source is used.
LC-MS can be used to detect compounds from poly-
aromatic (non-polar) to peptide & proteins.
GC-MS is still able to detect long chain aliphatic
compounds (petroleum based analytes) & very low mass
volatile material better than LC-MS.
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41. Very sensitive, very expensive, sample recovery is also
possible because IR is non-destructive technique.
In this, GC does the separation part where as IR perform
function of identification.
Effluent from GC is directly forwarded into the heated
pipe of IR at atmospheric pressure.
IR spectroscopy identifies the compound by identifying
the functional group. 41
GC-IR
Gas
Chromatography
Infrared
Spectroscopy
GC-IR
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Applications of GC-IR :
DNA analysis of blood samples, other fluids.
Pharmaceutical applications
Industrial applications
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45. 1. Fast and accurate analysis.
2. Higher degree of automation.
3. Higher sample throughput.
4. Better reproducibility.
5. Reduction of contamination due to its closed system.
6. Separation and quantification achieved at same time.
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Advantages of
Hyphenated Techniques:
46. 1. Kalpesh N Patel, et al ; Introduction to hyphenated techniques and their
applications in Pharmacy; Pharmaceutical Methods; Oct-Dec 2010; Vol 1 ;
Issue 1.
2. Silverstein R; Spectroscopic Identification of Organic Compounds; Wiley
Publication Delhi; 6th edition; 2009; Page 2-70
3. Skoog D et al; Fundamentals of Analytical Chemistry; Cengage Brain
Publication London; 9th edition; 2010; Page 16-25.
4. AH Beckett, J.B Stenlake, Pharmaceutical chemistry;4th edition-Part
2;Page 474-477.
5. Gurdeep R. Chatwal, K. Anand; Instrumental methods of chemical
analysis; Page 2.272,2.673
6. G. C. Stafford et al.; International Journal of Mass Spectrometry and Ion
Processes, 60; 1984, Page 85 and Analytical Chemistry, 59; 1987, Page
1677.
7. https://www.jic.ac.uk/services/metabolomics/topics/lcms/why.htm
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References