Temperament altogether refers to the use of gas chromatography and mass spectrometer stomrimeter. Mass spectrometry can be effective qualitative analysis, but the analysis of complex organic compounds appears to be powerless, and chromatography is an effective separation analysis method for organic compounds, especially suitable for quantitative analysis of organic compounds, but qualitative analysis is more difficult. Therefore, the effective combination of the two will provide chemists and biochemists with an efficient qualitative and quantitative analysis tools for complex organic compounds.
A technique like this that combines two or more methods is called a joint technology.
Temperament co-instrument is widely used in the separation and identification of complex components, which has the high resolution of GC and high sensitivity of mass spectrometry, is an effective tool for the qualitative and quantitative of drugs and metabolites in biological samples.
The basic components of a mass spectrometer are: three parts, which are placed in a vacuum general pipe.
Interface: The sample from the GC enters the mass spectrometer through the interface, which is the key to the temperament al-Co-use system.
Interface role
1 Pressure match - The vacuum of the mass spectrometry ion source is 10-3Pa, and the function of the GC column interface is to match the pressure between the two.
2 component selibency - there is a large amount of carrier gas in the gas flowing from the GC column, and the interface is to remove the carrier gas so that the measured substance is concentrated and enters the ion source.
Common interface technologies
1 Molecular separator connection (mainly used to fill columns) Diffusion type - Diffusion rate is inversely proportional to the square of the molecular weight of matter, and is proportional to its division pressure.
When the chromatography is through the separator, the small molecule's carrier is easily diffused from the micropores, pumped out by the vacuum pump, and the measured molecular weight is large, not easy to spread is concentrated.
2 Direct connection method (mainly used for capillary columns)
In the column and ion source between the length of about 50 cm, the internal diameter of 0.5mm stainless steel capillary connection, chromatography flow through the capillary tube all into the ion source, this interface technology sample utilization rate is high.
3 Open shunt connection The interface is to empty part of the chromatography, allowing the other part to enter the mass spectrometer, which removes the excess effluent by constantly flowing in to clean the helium.
The utilization rate of this method is low.
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