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Mass spectrometry

Mass spectrometry is an important enabling technology in bioscience in the 21st century. It is a unique research tool that detects chemical species with high sensitivity and high speed, offering at the same time a wealth of information on the investigated systems.

Our group members develop mass spectrometric methods that address challenging tasks, and have the potential to contribute to new discoveries. Examples of projects include: analysis of skin metabolites as well as analysis of natural compounds in complex matrices such as dairy products, tea, vegetables, and small metazoans.

One of the research projects focuses on coupling robotic arms with sample preparation stages and mass spectrometer as the detector.

This section will soon provide an overview of the main mass spectrometric techniques. Please report any errors to us.

Ion sourceAbbreviationAdvantagesDisadvantages
Electron ionizationEIRobust, suitable for non-polar volatile compoundsFragmentation, mainly suitable for analysis of small (volatile) molecules
Chemical ionizationCILess fragmentationLimited applicability, decomposition of thermally labile compounds
Electrospray ionizationESIExtremely useful in analysis of small and large molecules including biopolymers, multiply charged ions can be formed, high sensitivity, compatible with liquid chromatographyMultiply charged ions can be formed
Nanospray electrospray ionizationnanoESIExtremely useful in analysis of small and large molecules including biopolymers, multiply charged ions can be formed, high sensitivity, compatible with nanoflow liquid chromatographyMultiply charged ions can be formed
Atmospheric pressure chemical ionizationAPCISuitable for analysis of medium and non-polar analytesLess suitable for certain molecules such as macromolecules
Matrix-assisted laser desorption/ionizationMALDIExtremely useful in analysis of a wide range of molecules including biopolymers, can be used in MS imagingMatrix interference, sweet-spot effect
Surface-assisted laser desorption/ionizationSALDIVery useful in analysis of a wide range of molecules including biopolymers, less matrix interference, can be used in MS imagingSome variants have lower sensitivity
Secondary ion mass spectrometrySIMSVery high spatial resolution in SIMS imagingFragmentation
(variants of atmospheric pressure ionization, including: EESI, ESSI, DESI, nanoDESI, and many others)(too many to list here)Many of these methods are simple, easy to use, and do not require much sample preparationMany of these methods still require proper validation and proof of quantitative capabilities

In some experiments we use standard ion sources (EI and ESI). However, in many other experiments we implement home-made ion sources which are based on the designs published in scientific literature.

Mass analyzerAbbreviationAdvantagesDisadvantages
Magnetic field sectorBHigh resolution, suitable for isotope ratio analysisRelatively large, hard to interface with LC, often accompanied by E
Electric field sectorEFocusing and deflecting ionsRequires temporal scan (if used for separation of ions), often accompanied by B
QuadrupoleQSmall, inexpensive1 unit mass resolution
Ion trapITSmall, inexpensive, tandem MS capabilityLimited mass resolution, discontinuous operation makes it less suitable for quantitative analysis
Time-of-flightTOFGood mass resolution and accuracyLarge
Fourier transform ion cyclotrone resonanceFT-ICRExcellent mass resolution and accuracy, suitable for identification of molecules based on accurate/exact mass matchingVery expensive, very large, maintenance-intensive
Orbital ion trapOITExcellent mass resolution and accuracy, suitable for identification of molecules based on accurate/exact mass matchingVery expensive
Triple quadrupoleQQQOptimal for quantitative analysis, tandem MS capabilityRelatively expensive
Quadrupole - time-of-flightQ-TOFGood mass resolution and accuracy, tandem MS capabilityRelatively expensive, some models are large
Quadrupole - ion trapQ-ITHybrid of QQQ and IT, tandem MS capabilityRelatively expensive
Time-of-flight - time-of-flightTOF-TOFGood mass resolution and accuracy, tandem MS capabilityRelatively expensive, large

We implement ion trap and quadrupoles (single and triple) in most of our MS experiments. Access to other instruments is through collaborations.