There are many types of mass spectrometers, and the working principle and application range are also very different. From the application point of view, mass spectrometers can be divided into the following categories:
Organic mass spectrometer :
Due to different application characteristics, it is divided into:
1 gas chromatography-mass spectrometer (GC-MS). In this kind of instrument, due to the different working principle of the mass spectrometer, there are gas chromatography-quadrupole mass spectrometer, gas chromatography-time-of-flight mass spectrometer, gas chromatography-ion trap mass spectrometer and so on.
2 liquid chromatography-mass spectrometer (LC-MS). Similarly, there are liquid chromatography-quadrupole mass spectrometers, liquid chromatography-ion trap mass spectrometers, liquid chromatography-time-of-flight mass spectrometers, and various liquid chromatography-mass spectrometry-mass spectrometers.
3 other organic mass spectrometers, mainly include:
Matrix-assisted laser desorption time-of-flight mass spectrometer (MALDI-TOFMS);
Fourier transform mass spectrometer (FT-MS).
Inorganic mass spectrometers include:
1 spark source dual focus mass spectrometer.
2 inductively coupled plasma mass spectrometer (ICP-MS).
3 secondary ion mass spectrometer (SIMS).
Isotope mass spectrometer .
Gas analysis mass spectrometer : mainly exhaled mass spectrometer, helium mass spectrometer leak detector.
The above classifications are not very rigorous, as some instruments have different accessories and have different functions. For example, a gas chromatography-double-focus mass spectrometer, if switched to a fast atom bombardment ionization source, is no longer a gas chromatography-mass spectrometer, but a fast atom bombardment mass spectrometer (FABMS). In addition, some mass spectrometers can be connected to either a gas chromatograph or a liquid chromatograph, and therefore are not well classified. Among the above types of mass spectrometers, the most widely used ones are organic mass spectrometers.
In addition to the above classification, the mass spectrometer can be divided into a dual focus mass spectrometer, a quadrupole mass spectrometer, a time-of-flight mass spectrometer, an ion trap mass spectrometer, a Fourier transform mass spectrometer, etc., depending on the mass analyzer used in the mass spectrometer.
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Mass spectrometry technology has developed rapidly in recent years. With the development of mass spectrometry technology, the application fields of mass spectrometry technology are becoming more and more extensive. Because mass spectrometry has the advantages of high sensitivity, low sample consumption, fast analysis speed, simultaneous separation and identification, mass spectrometry is widely used in chemistry, document.write('') ​​chemical document.write('') Environment, document.write('') ​​energy document.write('') ​​, document.write('') ​​medical document.write(''), sports medicine, criminal investigation science, life sciences, materials science and other fields.
There are many kinds of mass spectrometers, and different instrument application characteristics are different. Generally, samples that can be vaporized at about 300C can be preferentially analyzed by GC-MS. Because GC-MS uses EI source, the mass spectrometry information obtained can be carried out. Library search. The separation effect of the capillary column is also good. If it can't be vaporized at around 300C, it needs to be analyzed by LC-MS. At this time, the molecular weight information is mainly obtained. If it is tandem mass spectrometry, some structural information can be obtained. If it is a biomacromolecule, it mainly uses LC-MS and MALDI-TOF analysis to obtain molecular weight information. For protein samples, the amino acid sequence can also be determined. The resolution of the mass spectrometer is an important technical indicator, and the high resolution mass spectrometer can provide a compound composition, which is very important for structural determination.
Double-focus mass spectrometers, Fourier transform mass spectrometers, time-of-flight mass spectrometers with reflectors, etc. all have high resolution capabilities.
Mass spectrometry has certain requirements for the sample. The sample to be analyzed by GC-MS should be an organic solution. The organic matter in the aqueous solution is generally not determined, and it must be extracted and separated into an organic solution, or a headspace sampling technique. Some of the compounds are too polar and easily decompose during heating, such as organic acid compounds. At this time, esterification treatment can be carried out, and the acid is converted into an ester and then subjected to GC-MS analysis, and the acid structure can be estimated from the analysis results. If the sample cannot be vaporized or esterified, then only LC-MS analysis can be performed. The sample subjected to LC-MS analysis is preferably an aqueous solution or a methanol solution, and the LC mobile phase should not contain a non-volatile salt. For polar samples, the ESI source is typically used, and for non-polar samples, the A document.write('') ​​PC document.write('') ​​I source is used.
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