The qualitative basis of chromatography is that under the same specific chromatographic conditions, different substances have different retention capacities on the stationary phase, so their retention times are also different, that is, their peak time is different, which can be used for qualitative analysis. In high-precision chromatography, the retention time can be accurate to a few tenths of a second. Qualitative information can be obtained from the chromatogram: there are several substances in the tested sample, and their approximate proportions, and the polarity of the compound can be roughly judged from the smoothness of the peak.
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The basis of qualitative and quantitative analysis of atomic emission spectrometry is to judge the composition of a substance by using the atomic or ion emission characteristic spectra of each element under thermal or electrical excitation, and to carry out qualitative and quantitative analysis of elements.
Atomic emission spectrometry can analyze about 70 elements. The detection limit can reach ppm, the accuracy is about 10%, and the linear range is about 2 orders of magnitude. This method can be effectively used to measure high, medium and low content elements. . High sensitivity, good selectivity and fast analysis speed.
Extended data:
Characteristics of atomic emission spectrometry:
1, which can simultaneously detect multiple elements, and each element simultaneously emits its own characteristic spectrum; The analysis speed is fast, the sample does not need to be processed, and dozens of elements are quantitatively analyzed at the same time (photoelectric direct reading instrument); Each highly selective element has a different characteristic spectrum;
2. The detection limit is low (10 ~ 0.1mg× g-1(general light source); Ng×g- 1(ICP) accuracy is 5% ~ 10% (general light source); & lt 1%(ICP)； ICP-AES has excellent linear performance in the range of 4 to 6 orders of magnitude, and can measure samples with high, medium and low content.