蔗糖，薄荷醇中旋光度检测方案(旋光仪)

Application Note s.c.o P-0002 Optical rotation measurement of sucrose and l-menthol Introduction Optical rotation is the property of substances， rotating the plane of polarization when linearly-polarizedlight passes through such substances. This is the property which occurs specifically to optical activesubstances in which the refractive indices of right and left circularly-polarized light are different. Opticalrotation that rotate light in a clockwise direction as viewed towards the light source is defined asdextrorotation (+) and the opposite， levorotation (-). The angle of rotated plane of polarization is called as optical rotation and polarimeter is the instrumentto measure such optical rotation. Optical rotation is proportional to cell pathlength and is related to sampleconcentration， measurement wavelength and temperature. The specific optical rotation [a]t is calculatedfrom the following formula using temperature t (℃)， wavelength x (nm)， cell pathlength 1 (dm)， sampleconcentration c (g/100 ml) and measured optical rotation a. JP， USP and EP suggest to measure optical rotation using D-line of Na lamp. Polarimeter is used for several purposes such as purity certification of sugar， verification ofpharmaceuticals and optical purity determination of optical active substances obtained from asymmetricsynthesis in organic chemistry field. Keywords： Optical rotation measurement， sucrose， menthol， ORD Optical rotation measurement of sucrose 5 g/100ml of sucrose (Wako PureChemical Industries， Ltd.， JIS specialgrade)Vwasprepared and measuredusing P-2000 with 100mm cell， Nalamp D-line under 20℃. Figure 1 shows the printout view ofmeasurement result.. The average ofoptical rotation in 5 times measurementwas++3.3264deg. and its specificoptical rotation calculated was+66.5280 which is in good agreementwith the specific optical rotation of5g/100ml sucrose solution described inJIS K0063 1)，+66.500. 5%Sucrose_20C.p1d [Data Information1 [Comment]Creation Date 2012/06/118：56 Sample name 5% Sucrose Comment [Measurement Information] UserInstrument Name Division P-2000Model Name P-2000 Company JASCOSerial No. A071661232 Light Source NaMonitor wavelength589nm D.I.T. 5 secNo.of cycle 5Cycle interval O secTemp. Monitor HolderTemp. Corr. FactorNoneAperture(S) 8.0nmAperture(L) 2.0nm Mode Optical RotationFactor 1 No. Sample No. Mode Calc. Data Meas. Data PMT Voltage[V] Temperature(C) 1 1 1-1 Specific O.R. +66.5348 +3.3267 243 19.99 2 2 1-2 Specific O.R. +66.5388 +3.3269 243 19.99 3 3 1-3 Specific O.R. +66.5368 +3.3268 243 19.99 4 4 1-4 Specific O.R. +66.5428 +3.3271 243 19.99 5 万 5 1-5 Specific O.R. +66.5388 +3.3269 243 19.99 6 6 Avg. +66.5384 7 7 S.D 0.0030 8 8 C.V 0.0045 Figure 1 Printout view of optical rotation measurement of 5g/100mlsucrose solution. Tel：+81-42-666-1322.Fax：+81-42-665-6512 P-0002 Optical rotation measurement of 1-menthol l-menthol(Wako Pure Chemical Industries， Ltd.) was prepared under the condition suggested in JP(2.5g ethanol (95)，25ml， 100mm) and its optical rotation was measured. Its specific optical rotation wascalculated to be[o]20=-50.01 which is well within the JP criteria： -45.0~-51.0. Generally， optical rotation is increased in shorter wavelength region. For optical rotation measurement，Na lamp D-line is usually applied， while when the optical rotation of the sample is very small using D-line，by irradiating shorter wavelength light， optical rotation can be measured in easier way. In this applicationdata， optical rotation measured using P-2000 with both Na lamp D-line and Hg lamp emission linewavelength (546，436，405，365 nm) and ORD spectrum (showing wavelength dispersion of opticalrotation) measured using J-820 +ORDM-401 were compared. As shown in Figure 2， both measuredvalues by P-2000 and ORDM-401 are very consistent. Like this， by employing shorter wavelength lightfor samples with small optical rotation， the measurement can be implemented easily.250 300 350 400 450 500 550 600 650 700 Wavelength (nm) Figure 2 Optical rotation of 1-menthol and comparison with ORD spectrum：P-2000 measured value ： ORD spectrum Reference (1) Optical rotation of sucrose solution described in JIS K0063 is referred to Handbook of Chemistry andPhysics， 42nd Edition (1960-1961)， P1784， The Chemical Rubber Co.， Ohio， U.S.A.. copyrightOJASCO CorporationJASCO INTERNATIONAL CO.， LTD- Sennin-cho -chome，Hachioji， Tokyo Japan The angle of rotated plane of polarization is called as optical rotation and polarimeter is the instrument to measure such optical rotation. Optical rotation is proportional to cell pathlength and is related to sample concentration, measurement wavelength and temperature. The specific optical rotation [a]tx is calculated from the following formula using temperature t (ºC), wavelength x (nm), cell pathlength 1 (dm), sample concentration c (g/100 ml) and measured optical rotation a.