how ions are detected in a mass spectrometer
The entire operation of the mass spectrometer, and often the sample introduction process also, is under complete data system control on modern mass spectrometers. For the reaction to occur, the proton affinity of the molecule M must be higher that the one of the gas molecule. Even electron fragment ions are often formed by rearrangement e.

Ion stream C has the heaviest particles and is deflected the least. The mass of the particles in ion stream B falls somewhere in between.

Notice that only one of the ion streams actually passes through the mass analyzer and reaches the detection unit at the back of the device.

how ions are detected in a mass spectrometer

The other two streams hit the side of the spectrometer and are neutralized. To analyze all of the ions, chemists mass spectrometer adjust the intensity of the magnetic field until each stream hits the detector.

how ions are detected in a mass spectrometer

A computer is used to analyze data collected at the detector and to display results in a graph known as a mass spectrum. On most graphs, the mass -- measured in atomic mass units amu -- is plotted on the x-axis. E veryone loves a rainbow and most people understand, at least roughly, how they work: Rain, then, is a brilliant method for separating sunlight.

Mass spectrometers

Chemists and physicists use a similar method for separating mixtures of substances into their components, turning them into beams of particles and then bending them with electricity and magnetism to make a kind of spectrum of different atoms that are easier to identify.

This technique is called mass spectrometry and it was pioneered by British physicist Francis Aston in Let's take a closer look at how it works! Rainbows bend short wavelength blue light more than long-wavelength red light. Mass spectrometers work in a very similar way. Mass spectrometers are much simpler than they look—or sound. Suppose someone gives you a bucketful of atoms of different chemical elements and asks you what's inside.

You need to separate out the atoms quickly and efficiently, but how do you do it? Tip your bucket into a mass spectrometer. It turns the atoms into ions electrically charged atoms with either too few or too many electrons. Then it separates the ions by passing them first through an electric field, then through a magnetic field, so they fan out into a spectrum.

A computerized detector tallies the ions in different parts of the spectrum and you can use this information to figure out what kinds of atoms were "mass spectrometer" in your bucket.

how ions are detected in a mass spectrometer

That's the basic idea, anyway. In reality, it's a bit more complex than this—there's no bucket, for a start!

how ions are detected in a mass spectrometer

A scientist uses a mass spectrometer in the Aeronomy Laboratory, Air Force Geophysics Laboratory AFGL. Photo by William W.

how ions are detected in a mass spectrometer

Magel courtesy of US Air Force. There are numerous different kinds of mass spectrometers, all working in slightly different ways, but the basic process involves broadly the same stages.

How Mass Spectrometry Works

Mass spectrometer designed by Robert Langmuir. Diagram courtesy of US Patent and Trademark Office. Although that's a very simplified explanation, it's not too far from what really happens. Take a look at this are detected of an early mass spectrometer designed by American electrical and electronic engineer Dr Robert V. You can apply exactly the same principle to atomic sized particles. An outline of what happens in a mass spectrometer Atoms can be deflected by magnetic fields - provided the atom is first turned into an ion.

The atom is ionised by knocking one or more electrons off to give a positive ion. This is true even for things which you would normally expect to spectrometer negative ions chlorine, for example or how ions form ions at all argon, for example. Mass spectrometers always spectrometer with positive ions.

how ions are detected in a mass spectrometer

The ions are how ions so that they all have the same kinetic energy. The ions are then deflected by a magnetic field according to their masses. The lighter they are, the more they are deflected.

how ions are detected in a mass spectrometer

The amount of deflection also depends on the number of positive charges on the ion - in other words, on how many electrons were knocked off in the first stage. The more the ion is charged, the more it gets deflected. The beam of ions passing through the machine is detected electrically.

A full diagram of a mass spectrometer. Understanding what's going on The detect for a vacuum It's important that the ions produced in the ionization mass have a free run through the machine without hitting air molecules. Deflection Different ions are deflected by the magnetic field by different amounts. The amount of deflection depends on: Lighter ions are deflected more than heavier ones.

How the Mass Spectrometer Works

Ions with 2 or more positive charges are deflected more than ones with only 1 positive charge. Detection Only ion stream B makes it right through the machine to the ion detector. By subscribing, you agree to the privacy policy and terms of service.

how ions are detected in a mass spectrometer

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Mass Spectrometry Tutorial

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1 thoughts on “How ions are detected in a mass spectrometer”

  1. Tylote says:

    Now all became clear, many thanks for an explanation.