用带有365nm汞灯的偏振仪测量氢溴酸右美沙芬的旋光度

本应用中，使用汞灯偏振仪（365nm）、卤素灯和干涉滤光片偏振仪（325nm）和ORD附件偏振仪测量氢溴酸右美沙芬。Application Note P-0001 Optical rotation of Dextromethorphan Hydrobromide measured using 365nm emission line of mercury lamp Introduction Optical rotation of Dextromethorphan Hydrobromide in accordance with the U.S. Pharmacopeia， is requested to be measured at 325 nm， however there is no emission l ine of 325 nm available in the polarimeter using Na lamp or Hg lamp as light source. Therefore， for the measurement of optical rotation of Dextromethorphan Hydrobromide， a polarimeter with halogen lamp as a light source and interference filter (325 nm) has been usually used， but as shown in Fig. 1， the optical rotatory dispersion (ORD) spectrum， there is a very steep slope in the short wavelength range near 325 nm， where even a very small error in the wavelength of interference f ilter may cause a very large error in the optical rotation measurement， which will makes the accurate measurements very difficult. On the other hand， if the measurement by using 365nm is allowed， since no wavelength error i s expected， the measurement of optical rotation can be implemented with much higher accuracy. In this experiment， Dextromethorphan Hydrobromidee was measured using polarimeter with Hg lamp (365 nm)， polarimeter with Halogen lamp and interference filter (325 nm) and polarimeter with ORD attachment . Keywords： Dextromethorphan Hydrobromide，Mercury lamp， Optical rotation， ORD spectrum Results Fig. 1 ORD spectrum of Dextromethorphan Hydrobromide Optical rotation (365 nm， 20℃)： +2.5655° (by JASCO P-2000 with Hg l amp) Specific rotation [α]36520： +142.53 Optical rotation (325 nm， 20℃)： +4.7034° (by JASCO P-2000 with halogen lamp & i nterference f ilter) Specific rotation [α]32520： +261.30 Optical rotation (365 nm， 20℃)：Specific rotation [α]36520：Optical rotation (325 nm， 20℃)：Speci f ic rotation [α]32520： +2.5706° (by JASCO P-2000 with ORD attachment) +142.81 +4.8726° (by JASCO P-2000 with ORD attachment)+270.70