- Spectroscopy and Spectral Analysis
- Vol. 43, Issue 3, 883 (2023)
Author Affiliations
DOI: 10.3964/j.issn.1000-0593(2023)03-0883-07 Cite this Article
Abstract
Jadeite is one of the most common jades in the current market, and the processing means to cover up the tiny defects on the surface of jadeite and improve its luster by waxing is commonly accepted by consumers. The waxing of A jadeite, B and B+C jadeite and B and B+C jadeite will fluoresce under a UV lamp after waxing, and how to identify these jadeites quickly and effectively is a problem that needs to be solved now. The common A, B, B+C jadeite and two kinds of optimized waxes in the current market were collected, and the optimized waxes were used to wax this jadeite, and the samples before and after waxing were systematically compared and studied by using a UV fluorescent lamp, and infrared spectrometer and fluorescence spectrometer. The results showed that the A jadeite did not fluoresce under UV fluorescent light, the B and B+C jadeite had weak-medium fluorescence, and all the jadeites emitted similar fluorescence after waxing. Infrared spectroscopy direct transmission method showed that the absorption peaks of 3 064, 3 032, 3 003 cm-1 were generated by the stretching vibration of the functional group ν(C—H) on the aromatic ring of the aromatic compounds in the functional group area of B and B+C jadeite; the high-quality waxes were generated by the stretching vibration of the functional group ν(—CH2—) of the alkane compounds absorption peaks at 2 915, 2 846 cm-1 and possibly 1 681 cm-1 due to the stretching vibration of the functional group ν(CO),respectively. In contrast, only absorption peaks from methyl and methylene groups were detected in Chuan wax. The fluorescence spectra showed no fluorescence response for A jadeite and fluorescence response for B and B+C jadeite. The high similarity of the profiles of some B+C jadeite and B jadeite indicates that the filling emits the fluorescence, and the ions in the dyes cause the fluorescence peaks to be shifted and the fluorescence intensity to change. According to the B+C, jadeite fluorescence peak position can be divided into three categories, excitation wavelengths were 350, 358, 370 nm, and emission wavelengths were 370, 420, 414/434 nm. Two optimized wax fluorescence peak is different, and the quality of wax fluorescence intensity is higher than Chuan wax. After waxing, the fluorescence peak of A jadeite will appear. The fluorescence intensity is related to the concentration of wax on the surface of jadeite, B and B+C jadeite will also appear after waxing, the fluorescence peak of optimized wax, but because the concentration of optimized wax is low, the strongest fluorescence peak is issued by the filling of jadeite and compared to the wax before, the fluorescence peak has redshift. Fluorescence spectroscopy can be used as a fast and non-destructive detection means to distinguish A, B and B+C jadeite before and after waxing, and the A jadeite and B or B+C jadeite after waxing can also be effectively distinguished, perfecting the basis on which fluorescence spectroscopy can be widely used in the jadeite market.
Keywords
Fluorescence spectraInfrared spectroscopyJadeiteWaxing jadeite
