计算化合物分子式的五种方法

计算化合物分子式的五种方法包括高分辨质谱法 ( HRMS) ,高分辨质谱数据法 ( HRMS data) ,元素分析法 ( EA) ,1 3 C-核磁共振 ( COM,DEPT)数据法 ( 1 3 C-NMR( COM,DEPT) data)和三相似法。第一种方法 :根据 HRMS测得的分子量精确值 M和环加双键数 ( r+db) ,推断出化合物的分子式。第二种方法 :计算分子式的方法与第一种方法相类似 ,只不过是首先应按照测得的精确分子量的尾数 ,估算出分子式的总含氢原子数 ,然后再确定分子式。第三种方法 :按照 HRMS测量的 M、( r+db)和 EA测量的化合物的组成元素百分比含量 ,计算分子式。第四种方法 :根据 1 3 C-NMR测量的化合物分子各组成功能团的数目来确认分子式。第五种方法 :通过被测化合物的特征离子质谱与共同的分子式 CH3 ( CH2 ) n COR进行比较后 ,推断出分子式 ,例如柱晶白霉素、麦地霉素和生枝霉素具有共同的分子式 C3 5H56NO1 3 RR1 R2 ,其差别仅是它们的 R、R1 和 R2 不同。

Five Calculating Methods for the Molecular Formula of Compounds

Five methods of the molecular formula of calculated compounds consist of high resolution mass spectrometer (HRMS), high resolution mass spectrometer data(HRMS data), element analysis(EA), 13 C nuclear magnetic resonace(COM, DEPT) data( 13 C NMR data (COM,DEPT)) and three fact simularity. (1) The molecular formula of compound was supposed on the basis of precise molecular weight (M) and cycles plus double bonds (r db) measured b HRMS. (2) The calculation method is siminary with the previous, but the hydrogen atom amounts in molecular formula have been estimated to go by decimal of precise molecular weight at first. (3) The molecular formula of compound was determined according to the precise molecular weight and cycles plus double and the elemental percentage content by HRMS and EA. (4)It was calculated to go by amounts of the various functional groups acquired by 13 C NMR. (5) On the basis of comparison between the characteristic ion mass spectra and the common molecular formula CH 3(CH 2) nCOR, the detected mo lecular formula was centified, for example, Leucomycins, Mide camycins and Shenjimycins have the common molecular formula C 35 H 56 NO 13 RR 1R 2, their differences are only the different R, R 1 and R 2.