LC-MS is a combination of what it is and what it is to achieve the complementary advantages of multiple instruments: chromatography and mass spectrometry.
Extended information:
Liquid chromatography-mass spectrometry (HLPC-MS) is also called liquid chromatography-mass spectrometry technology. It uses liquid chromatography as the separation system and mass spectrometry as the detection system. . The sample is separated from the mobile phase in the mass spectrometer part. After being ionized, the mass analyzer of the mass spectrometer separates the ion fragments according to their mass numbers, and the mass spectrum is obtained through the detector.
LC-MS embodies the complementarity of the advantages of chromatography and mass spectrometry. It combines the high separation ability of chromatography for complex samples with the advantages of high selectivity, high sensitivity and the ability of MS to provide relative molecular mass and structural information. Combined, it has been widely used in many fields such as pharmaceutical analysis, food analysis and environmental analysis.
To achieve this goal, a device that acts as an "interface" is needed to connect the liquid phase and the mass spectrometer.
Since the early 1970s, people have begun to devote themselves to the research of liquid-mass spectrometry interface technology. In the first 20 years, it was in a slow development stage, and many kinds of joint interfaces were developed, but none of them were used in commercial production. It was not until the advent of atmospheric pressure ionization interface technology that liquid-mass spectrometry developed rapidly and was widely used in laboratory analysis and applications.
In 1972, Tal'roze et al. proposed the idea of ??directly introducing the chromatographic column outlet into the mass spectrometer, which was called the capillary inlet interface at the time.
Many research groups have successively carried out research in this area, and in 1980 this liquid-mass interface was used for commercial production. In order to avoid contamination from non-volatile solvents, Melera improved this interface using a small diaphragm and developed direct liquid introduction interface technology.
This interface allows the liquid chromatography mobile phase to flow along the injection rod, and then through a pinhole with a diameter of 3 to 5 μm to inject the liquid into the CI ion source of the mass spectrometer.
The chromatograph can be easily connected or disconnected from the mass spectrometer using a traditional CI ion source. The advantages of the direct liquid introduction interface are: simple interface, low cost, and can gently convert non-volatile and thermally unstable compounds into gaseous state. The sample enters the mass spectrometer in a solution state to form CI conditions, and molecular weight information can be obtained.
The disadvantages are: a large amount of mobile phase needs to be reduced during the splitting process, and the separator used is often clogged.