Did you watch N.C.I.S? Then, can you tell us what was Abby Sciuto (Pauley Perrette) lab babe's name?.... Yes! it's the "Mass spectrometer", today we post an introduction about the general use of Mass spectrometer.
"Mass spectrometry (MS) is an analytical chemistry technique that
measures the mass-to-charge ratio and abundance of gas-phase ions.A mass
spectrum (plural spectra) is a plot of the ion signal as a function of
the mass-to-charge ratio. The spectra are used to determine the
elemental or isotopic signature of a sample, the masses of particles and
of molecules, and to elucidate the chemical structures of molecules,
such as peptides and other chemical compounds. Mass spectrometry works
by ionizing chemical compounds to generate charged molecules or molecule
fragments and measuring their mass-to-charge ratios.In a typical MS procedure, a sample, which may be solid, liquid, or gas, is ionized, for example by bombarding it with electrons. This may cause some of the sample's molecules to break into charged fragments. These ions are then separated according to their mass-to-charge ratio, typically by accelerating them and subjecting them to an electric or magnetic field: ions of the same mass-to-charge ratio will undergo the same amount of deflection.The ions are detected by a mechanism capable of detecting charged particles, such as an electron multiplier. Results are displayed as spectra of the relative abundance of detected ions as a function of the mass-to-charge ratio. The atoms or molecules in the sample can be identified by correlating known masses to the identified masses or through a characteristic fragmentation pattern." -Wikipedia-
How the mass spectrometer works?
If something is moving and you subject it to a sideways force, instead of moving in a straight line, it will move in a curve - deflected out of its original path by the sideways force.
Suppose you had a cannonball travelling past you and you wanted to deflect it as it went by you. All you've got is a jet of water from a hose-pipe that you can squirt at it. Frankly, its not going to make a lot of difference! Because the cannonball is so heavy, it will hardly be deflected at all from its original course.
But suppose instead, you tried to deflect a table tennis ball travelling at the same speed as the cannonball using the same jet of water. Because this ball is so light, you will get a huge deflection.
The amount of deflection you will get for a given sideways force depends on the mass of the ball. If you knew the speed of the ball and the size of the force, you could calculate the mass of the ball if you knew what sort of curved path it was deflected through. The less the deflection, the heavier the ball.
The same principle can be applyed to atomic sized particules.
The instrument consists of three major components:
- Ion Source: For producing gaseous ions from the substance being studied.
- Analyzer: For resolving the ions into their characteristics mass components according to their mass-to-charge ratio.
- Detector System: For detecting the ions and recording the relative abundance of each of the resolved ionic species.
With all the above components, a mass spectrometer should always perform the following processes:
- Produce ions from the sample in the ionization source.
- Separate these ions according to their mass-to-charge ratio in the mass analyzer.
- Eventually, fragment the selected ions and analyze the fragments in a second analyzer.
- Detect the ions emerging from the last analyzer and measure their abundance with the detector that converts the ions into electrical signals.
- Process the signals from the detector that are transmitted to the computer and control the instrument using feedback.
General Applications of Mass Spectrometry:
•Environmental analysis
•Forensic analysis
•Clinical research
•Proteomics and genomics
•Generation of physico-chemical data
In the next parts we will talk about the mass spectrometry applications in Forensic analysis.
See You :)
•Environmental analysis
•Forensic analysis
•Clinical research
•Proteomics and genomics
•Generation of physico-chemical data
In the next parts we will talk about the mass spectrometry applications in Forensic analysis.
See You :)
