Liquid chromatography-mass spectrometry experiment

Summary

This experiment is from the official website of Wuhan University School of Pharmacy

Operation method

Liquid chromatography-mass spectrometry experiment

Principle

Mass spectrometry is an analytical method that analyzes a sample by determining the mass-to-charge ratio of the ions of the sample being measured. The sample to be analyzed is first ionized, and then the mass spectrum is obtained by separating the ions according to their mass-to-charge ratio (m/z) by using the difference in the motion behavior of different ions in the electric or magnetic field, and the qualitative and quantitative results of the sample can be obtained through the mass spectrum of the sample and the related information. Mass spectrometry is a method for qualitative and quantitative analysis of samples by analyzing the mass-to-charge ratios of the ions in the samples. Therefore, the mass spectrometer must have an ionization device to ionize the sample into ions, there is a mass analysis device to separate the ions of different mass-to-charge ratios, the detector can be detected by the sample's mass spectra, due to organic samples, inorganic samples and isotope samples have different forms, properties and different analytical requirements, so the ionization device, mass analysis device and detection device used are different. However, regardless of the type of mass spectrometer, the basic composition is the same. All include an ion source, mass analyzer, detector and vacuum system. A mass spectrometer is a good instrument for qualitative identification and is not useful for analyzing mixtures. Chromatograph is a very good instrument for separation, but the qualitative ability is very poor, the combination of the two, can play their respective expertise, so that the separation and identification at the same time. Therefore, as early as the 1960s began the study of gas chromatography - mass spectrometry coupling technology, and the emergence of early gas chromatography - mass spectrometry coupling instrument. At the end of the 1970s, this kind of coupling instrument had reached a high level. At the same time, research on liquid chromatography-mass spectrometry began. In the late 80's, the emergence of atmospheric pressure ionization technology improved the level of liquid chromatography-mass spectrometry to a new stage. At present, in the organic mass spectrometer, in addition to laser desorption ionization - time-of-flight mass spectrometer and Fourier transform mass spectrometer, all mass spectrometers are and gas chromatography or liquid chromatography to form a joint instrument. This makes the mass spectrometer very convenient for both qualitative and quantitative analysis.

Move

1. Enrichment and clean-up of water samples used by Oasos HLB solid phase extraction columns.

2. Prepare 5 mmol-L-1 acetic acid - ammonium acetate buffer solution (pH = 4.5), a standard solution of monochlorophenol isomers.

3. A C8 column (250 mm×4.0 mm×5 μm) was set up with acetic acid - ammonium acetate buffer solution/acetonitrile/methanol (65:28:7) as the mobile phase.

4. Refer to the operating instructions of the instrument to carry out the experiment.

Common Problems

1. Analyze the mass spectrometry profile.

2. Evaluate the method based on the experimental data obtained, including precision and stability.

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