Chromato-mass spectrometry is by far the most accurate way to determine what substances a mixture consists of. For this, the mixture is passed through a chromatographic column filled with an adsorbent substance. The adsorbent slows down the movement of the components of the mixture, but for different molecules the degree of this slowdown is different. As a result, molecules of different compositions, like runners in a mass race, come to the finish line at different times – the exit from the column. The task of the chromatographer-researcher is to find specific adsorbents in order to better separate the molecules.
Then the mass spectrometer ionizes the molecules (in this case, complex molecules are partially destroyed, and then their fragments are analyzed, which expands the possibilities for determining the structure of a substance), accelerates them in an electric field in a vacuum, and then places them in a magnetic field. In a magnetic field, ions with different mass-to-charge ratios will move differently. Next is the detector, which registers the number of ions that have reached the target at one time or another. Thus, the ratio of the mass of the molecule to its charge is determined. The results are presented in the form of a graph of the distribution of ions by their mass numbers. The chart looks like a series of vertical lines of different heights and resembles a line spectrum. Because of this graphical representation, the method was called “mass spectrometry”, although there is nothing more spectral in it.
The mass spectrum for a molecule is as unique as a fingerprint is for a person, and by looking at the mass spectrum, you can tell exactly which substance it corresponds to. If, of course, this mass spectrum is available in the card index (that is, in the database, or, as they say, in the library of mass spectra).
Mass spectrometry is very sensitive and can detect compounds in trace concentrations – a few molecules per billion. This concentration does not change the color, odor, or transparency of the solution. But at the same time, it can have a negative (or positive) effect on living beings.
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