subject: Accumulation Spectrometry Tesca [print this page] Introduction Introduction
Mass spectrometers are instruments that the nature of the molecules in a sample to identify the formation of ions of the sample molecules. These ions are accelerated by an electric field, and then through a magnetic field that is classified in accordance with the mass ratio (m / z) calculated. The formation of ions often breaks down molecules in the charged fragments, which are characteristic of the parent compound. The amount of each fragment is represented as a spectral structure, and a mass spectrum of the compound can be used for the qualitative determination.
Method is that the mass of fragments of molecules can be used to define the structure and the mass of the molecule "original built up determination.
Analyzing the paper, therefore, that the "molecular weight" and "weight of the fragments reference data are compared with the identity of the sample to be determined. Is possible because each mass spectrum substances so long as the mass relative to the correct adjustment of the output, or vice versa.
Process Description
Is the simple description of the mass spectrometer comprises a sample inlet, an ionization source, an ion accelerator, a development and a mass detector. More complex also use a filter for the energy-mass of the development in order to achieve accurate mass assignments. Of course there are many variations of the "mass", but due to insufficient space here to look at the mass spectrometry and classical base.
The coupons are in a mass spectrometer is present in the vapor phase to ensure that the sample is to be understood as a gas, the sample well kept above room temperature, and sometimes up to 400 C.
The following steps illustrate:
1. Example enters the ionization assembly room, is heated and turns to gas
2. With a far above the ground voltage, a beam of electrons is accelerated
3. With the far above the ground voltage electrons, sample molecules are ionized and shattered (producing well-defined fragments)
4. Every piece is then travels to the accelerator as 'an human being Particle'
5. Under the influence of the accelerating voltage, the charged particles velocities increase in the acceleration chamber
6. Ions in the magnetic field that only the load of the particular mass passes. For different mass, so that all fragments reach the detector varies the magnetic field. The ions at the detector, amplify the original signal is transmitted to a computer for the processing and analysis.
The output is in the form of a series of nodes of a graph, which is generated as a "mass spectrum". Each "peak" value is equal to a fragment mass. The detected fragments having a particular mass are more intense at the tip. "
Output Analysis
Under certain controlled conditions each substance characteristic mass spectra. This makes it possible to prepare a sample to be identified by comparison of its mass spectrum with those of known compounds. When measuring the relative intensities of the mass spectra, it is possible for the quantitative analysis.
A peak in the mass spectrum of the molecule is fragmented, as a "parent ion or molecular ion" is the largest mass, and discovered that the molecular weight of the sample is examined. Some of the other peaks in the mass spectrum show the structure of the molecule Is sometimes difficult for analysis by mass spectrometry of the main peak, and therefore the molecular weight of the sample to be found.
