1.Isolation and identification of non alkaloid components from Tinospora hainanensis (Ⅲ)
Lianbo LIN ; Xiaowen FU ; Youying GUO ; Al ET ;
Chinese Traditional and Herbal Drugs 1994;0(01):-
Object To study the chemical constituents of a new species belonging to genus Tinospora (Menispermaceae)— the Tinospora hainanensis H S Lo et Z X Li Methods Isolation and purification were carried out on silica gel column, identified by physico chemical properties and structurally elucidated by spectral analysis Results 4 non alkaloids were obtained They were 24 epi makisterone A (Ⅰ), octacosanoic acid (Ⅱ), octacosyl alcohol (Ⅲ) and hexacosyl alcohol (Ⅳ) Conclusion All of the 4 compounds were obtained from this plant for the first time, and compounds Ⅰ, Ⅱ and Ⅳ were obtained from genus Tinospora for the first time
2.Quantitative Analysis of Soil by Laser-induced Breakdown Spectroscopy Using Genetic Algorithm-Partial Least Squares
Xiaoheng ZOU ; Zhongqi HAO ; Rongxing YI ; Lianbo GUO ; Meng SHEN ; Xiangyou LI ; Zemin WANG ; Xiaoyan ZENG ; Yongfeng LU
Chinese Journal of Analytical Chemistry 2015;(2):181-186
Laser-induced breakdown spectroscopy ( LIBS) was used to detect the compositions of soil in the air, and the quantitative analysis model with genetic algorithm-partial least squares ( GA-PLS ) was established. A total of fifty-eight soil samples were split into calibration, monitoring and prediction sets. Eleven soil compositions including Mn, Cr, Cu, Pb, Ba, Al2 O3 , CaO, Fe2 O3 , MgO, Na2 O, and K2 O were quantitatively analyzed. The results demonstrated that, as a pretreatment method for optimizing the selection of spectral lines, GA could be effectively used to reduce the number of spectral lines for use in building PLS model, and hence simplify the quantitative analysis model. More importantly, for most of the soil compositions, GA-PLS could significantly improve the prediction ability compared with the conventional PLS model. Take Mn as an example, the root-mean-square error of prediction ( RMSEP ) was decreased from 0. 0215% to 0 . 0167%, and the mean percent prediction error ( MPE ) was decreased from 8 . 10% to 5 . 20%. The research provides an approach for further improving the accuracy of LIBS quantitative analysis in soil.