Mass spectroscopy is one of the most important techniques to evaluate molecular weight. Mass spectroscopy provides key information on a molecule’s mass, structure and chemical properties. It is used to identify unknown materials and for the quantification of known substances.
Mass Spectrometer Function
Most mass spectrometers function using the same general mechanism. First, sample molecules are introduced to the sample inlet. An ion source charges the sample molecules into ions. Typical ionization techniques involve chemical and electron ionization for gas samples, MALDI and ESI for liquids and solids, and inductively coupled plasma (ICP) for cation analysis.
A mass analyzer is then used to separate the ions according to m/z (mass/charge). Common mass analyzer types used include quad TOF, time of flight, quadrupole, and ion trap.
Common Mass Spectrometer Systems
ICP/MS uses inductively coupled plasma for sample ionization and a mass spectrometer for ion separation and quantification. Useful in trace metal analysis, forensic toxicology, clinical diagnostics, and environmental testing.
Considerations for ICP/MS systems include the data handling capabilities of the system, customization options, sensitivity and dynamic range.
Top pick for ICP/MS systems is the iCAP™ TQ ICP-MS from Thermo Fisher Scientific.
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometers combine the MALDI ionization source and the TOF mass analyzer. The TOF mass analyzer measures the ion’s m/z ratio and the MALDI ionization source ensures the sample is volatilized and ionized. A key application area for MADLI TOF MS is the biological sciences.
Considerations for MALDI TOF mass spectrometers include the necessity for tandem configuration, resolution and mass range.
Top pick for MALDI TOF MS systems is the rapifleX MALDI-TOF/TOF System from Bruker Daltonics.
LC/MS relies on a liquid-phase separation system and a mass spectrometer to couple sample fractionation and analysis. Typical LC systems include HPLC, UPLC and nano-LC. In an LC/MS, column flow is continuous and a fast mass analyzer that can keep up is imperative. This is useful in a variety of applications involving liquid sample analysis including proteomics and life science analyses.
Considerations for LC/MS systems include ionization method, mass analyzer, scanning speed, and resolution.
Top pick for LC/MS systems is the timsTOF Pro Mass Spectrometer from Bruker Daltonics.
GC/MS combines gas chromatography with a mass spectrometer to separate and analyze gas-phase molecules. Volatile compounds are injected into a flowing gas stream, coated with stationary phase material and separated as the stream flows a long hollow tube. Fractionated compounds are then ionized and injected into the mass spectrometer analyzer. GC/MS systems are great for analyzing small, relatively non-polar compounds and used in food, environmental, petrochemical and forensic science applications.
Considerations for GC/MS systems include temperature range, ionization method, mass analyzer, and mass range.
Top pick for GC/MS systems is the Pegasus BT 4D GCxGC Time-of-Flight Mass Spectrometer from LECO.
Applications of Mass Spectrometers
Mass spectrometers are a cornerstone technology for any analytical laboratory. Some of the most exciting scientific research rely on this instrument for analysis. Applications of mass spectrometers include:
Chris Cicinelli is the Editor of Labcompare.