Four Common Chemical Analysis Methods

Here are four common chemical analysis methods:

In the field of detection, there are four famous spectra, namely chromatography, spectrometry, mass spectrometry and spectrometry, which have their own advantages and disadvantages. In order to give full play to the advantages of each analytical instrument, two or three instruments can be combined to analyze samples, and the combined technology can overcome the defects when the instruments are used alone. It is the development trend of analytical instruments in the future.

Brief introduction of four commonly used analysis methods:

Mass spectrometry: analyzing the mass of molecules, atoms or atomic groups can infer the composition of substances, which is generally used for qualitative analysis and quantitative analysis.

Chromatography: It is both a means of separation and quantitative analysis, which can distinguish different substances in samples.

Spectrum: qualitative analysis, to determine the main groups in the sample, to determine the category of substances. From infrared to x-ray, they are all spectra, and their application ranges are very different. Is to analyze the spectral properties of molecules or atoms.

Spectrum: Generally, it refers to four major spectra: nuclear magnetic resonance (NMR), mass spectrometry-mass spectrometry (ms), vibration spectrum-infrared/Raman (IR/Raman) and electron transition-ultraviolet (UV).

Spectral analysis method

superiority

(1) Fast analysis speed: Atomic emission spectrometry can be used for analysis before steelmaking furnace, and the analysis results of more than 20 elements can be given simultaneously in L ~ 2 minutes.

(2) Simple operation: Some samples can be directly subjected to spectral analysis without any chemical treatment. With the development of computer technology, it is sometimes possible to automatically analyze, process data and analyze results by pressing the keyboard. In poison alarm, air pollution detection and so on. Molecular spectroscopy is used for telemetry, and it is not necessary to collect samples, so it can give an alarm or detect the degree of pollution within a few seconds.

(3) No pure sample is needed: only the known spectrogram can be used for spectral qualitative analysis. This is a very outstanding advantage of spectral analysis.

(4) Multiple elements or compounds can be determined at the same time, and complicated separation operation is omitted.

(5) Good selectivity: elements and compounds with similar chemical properties can be determined. For example, the spectral lines of niobium, tantalum, zirconium, hafnium and mixed rare earth oxides can be separated and do not interfere with each other, making them a powerful tool for analyzing these compounds.

(6) High sensitivity: trace analysis can be carried out by spectrometry. At present, the relative sensitivity can reach one in ten million to one in one billion, and the absolute sensitivity can reach 10-8g~ 10-9g.

(7) Less sample damage: it can be used in antiquities, criminal investigation and other fields.

The adoption of new technology (such as the application of plasma light source) broadens the linear range of quantitative analysis, and can simultaneously determine elements with different high and low contents. Microanalysis can also be carried out.

Limitations: Spectral quantitative analysis is based on relative comparison, and it is often difficult to have a set of standard samples as a benchmark. The composition and structural state of the standard samples should be basically the same as the analyzed samples.