10 Questions
What determines the degree of compound separation in LC-MS?
The interaction of compounds with the stationary and mobile phases
What is the primary difference between HPLC and LC?
The pressure of the mobile phase
What is the advantage of using LC-MS over other methods?
It provides extensive sample coverage
What is the original name of HPLC?
High-pressure liquid chromatography
What is the name of the mass spectrometer mentioned in the text?
LTQ-0001
How do the compounds' interactions with the stationary and mobile phases affect the sample's components?
They affect the degree of compound separation
What is the pressure range in which HPLC operates?
Between 50 and 350 bar
What is the main difference in how the mobile phase moves through the column between LC and HPLC?
LC uses gravity, while HPLC uses pumps
What is the advantage of using multiple column chemistries, including reversed phase liquid chromatography?
It provides extensive sample coverage
What is the relationship between HPLC and LC?
HPLC is an advancement over LC
Study Notes
Basic Principle
- Mass spectrometry is a powerful quantitative and qualitative analytical technique.
- It is used to study atoms, molecules, and macromolecules.
- It requires the sample to evaporate or sublimate without thermal decomposition.
Equipment
- All mass spectrometers consist of:
- Ion source
- Vacuum system
- Mass analyzers
- Detector
- Computer
How it Works
- Introduction of the sample
- Derivatization of compounds (if necessary)
- Ionization (production of ions)
- Acceleration (ions sorted and separated according to their mass and charge)
- Detection (results detected and recorded)
Applications
- Identification of drug usage markers in urine, blood, and saliva
- Identification of structures of biomolecules
- Molecular mass determination of known and unknown samples
- Specific medical procedures (e.g., gas composition in breathing)
Instrumentation Comparison
- Liquid Chromatography (LC):
- Separates liquids with multiple components
- Analyzes polar and nonpolar analytes
- Gas Chromatography (GC):
- Analyzes biological compounds
- Used for drug screening, pesticide detection, and inborn errors of metabolism
Troubleshooting
- Signal instability causing inaccuracy of results
- Decrease in sensitivity (contamination, etc.)
- Discrepancy of mass to charge ratio (m/z)
- High degree of expertise required for performance and maintenance
- Elevated cost of machinery
QC Type/Calibration
- Regular calibration is necessary for accurate results
Who Performs this Assay?
- Tandem mass spectrometry should be performed byMLS only
- Liquid Chromatography-Mass Spectrometry can be performed by MLS or MLT with MLS supervision
Tests Types
- Tandem mass spectrometry: MLS only
- Liquid Chromatography-Mass Spectrometry: MLS/MLT
Tandem Mass Spectrometer
- Uses the mass to charge (m/z) ratio to separate and identify analytes
- Excellent for plasma with a large number of backdrop elements
- Benefits of MS/MS include:
- Enhances the quantity of assays that may be run on dried blood spot type samples
- Minimal false positive rate
- Fast results (20 tests in about 2 minutes)
Liquid Chromatography
- Separates chemicals from a sample before analysis
- Compounds are separated based on their interactions with the stationary and mobile phases
- Provides extensive sample coverage with various column chemistries (e.g., reversed phase LC)
- High Performance Liquid Chromatography (HPLC) is an advancement over LC, operating at higher pressures (50-350 bar)
Basic Principle
- Mass spectrometry is a powerful quantitative and qualitative analytical technique.
- It is used to study atoms, molecules, and macromolecules.
- It requires the sample to evaporate or sublimate without thermal decomposition.
Equipment
- All mass spectrometers consist of:
- Ion source
- Vacuum system
- Mass analyzers
- Detector
- Computer
How it Works
- Introduction of the sample
- Derivatization of compounds (if necessary)
- Ionization (production of ions)
- Acceleration (ions sorted and separated according to their mass and charge)
- Detection (results detected and recorded)
Applications
- Identification of drug usage markers in urine, blood, and saliva
- Identification of structures of biomolecules
- Molecular mass determination of known and unknown samples
- Specific medical procedures (e.g., gas composition in breathing)
Instrumentation Comparison
- Liquid Chromatography (LC):
- Separates liquids with multiple components
- Analyzes polar and nonpolar analytes
- Gas Chromatography (GC):
- Analyzes biological compounds
- Used for drug screening, pesticide detection, and inborn errors of metabolism
Troubleshooting
- Signal instability causing inaccuracy of results
- Decrease in sensitivity (contamination, etc.)
- Discrepancy of mass to charge ratio (m/z)
- High degree of expertise required for performance and maintenance
- Elevated cost of machinery
QC Type/Calibration
- Regular calibration is necessary for accurate results
Who Performs this Assay?
- Tandem mass spectrometry should be performed byMLS only
- Liquid Chromatography-Mass Spectrometry can be performed by MLS or MLT with MLS supervision
Tests Types
- Tandem mass spectrometry: MLS only
- Liquid Chromatography-Mass Spectrometry: MLS/MLT
Tandem Mass Spectrometer
- Uses the mass to charge (m/z) ratio to separate and identify analytes
- Excellent for plasma with a large number of backdrop elements
- Benefits of MS/MS include:
- Enhances the quantity of assays that may be run on dried blood spot type samples
- Minimal false positive rate
- Fast results (20 tests in about 2 minutes)
Liquid Chromatography
- Separates chemicals from a sample before analysis
- Compounds are separated based on their interactions with the stationary and mobile phases
- Provides extensive sample coverage with various column chemistries (e.g., reversed phase LC)
- High Performance Liquid Chromatography (HPLC) is an advancement over LC, operating at higher pressures (50-350 bar)
Understanding the basics of mass spectrometry, including its application, equipment, and working principles. This technique is used to study atoms, molecules, and macromolecules.
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