中国药科大学专业英语

UV:The visible region corresponds to 800 to 400 nm,and the ultraviolet region to400nm to 200nm.The wavelength at which absorption is a maximum is referred to as the λmax of the sample.The absorbance A of a sample is proportional to its concentration in solution and the path length through which the beam of ultraviolet radiation passes.To correct for concention and path length ,absorbance is convered to molar absorptivity e by dividing it by the concentration c in moles per liter and the path length l in centimeters.红外①While NMR spectroscopy is,in general,more revealing of the structure of an unkown compound,IR still remains an important place in the chemist’s inventory of spectroscopic methods because of its usefulness in identifying the presence of certain functional groups within a molecule.②wave numbers are reciprocal centimeters,so the region 2.5 to 16 corresponds to 4000 to 625cm .an advantang using wave numbers is that they are directly proporthus,tional to energy while wavelengths are inversely proportional to energy. Thus 4000cm is the high-energy end of the scale and 625 cm is the low-energy end. Almost all organic compounds exhibit a peak or peaks near 3000 cm because it is in this region that absorption due to carbon-hydrogen stretching vibrations occurs.The peaks at 1460 ,1380,and725cm-1 are due to various bending vibrations.③In using infrared spectroscopy for structure determination,peaks in the range 1600to 4000cm-1 are usually emphasized because this is the region in which the vibrations characteristic of particular functional groups are found .the region 1300 to 625cm-1 is known as the fingerprint region.It is here that the pattern of peaks varies most from compound to compound.质谱① It does not depend on the selective absorption of particular frequencies of electromagnetic radiation but rather examines what happens to a molecule，when itis bombarded with high-energy electrons.②The molecular ion has the same mass(less the negligible mass of a single electron)as the molecule from which it is formed.③Scanning all m/z values gives the distribution of positive ions ,called amass spectrum,characteristic of a particular compound.氢谱①The orientation of the spectrum on the chart is adjusted electronically so that the TMS peak coincides with the zero grid line.②A 60-MHZ nmr spectrometer separates the energy of nuclear spin states only 60 percent as much as does a 100-MHZ spectrometer.③By reporting chemical shifts in parts per million,this effect fo field strength is taken into account:thus irrespective of magnetic field strength.The signal due to the protonof chloroform appears at 7.28 ppm.总论①The number of signals in a H nmr molecule;the integrated areas tell us their relative ratios;their chemical shifts indicate the kind of environment surrounding the proton:and the splitting pattern is related to the number of protons on adjacent carbons.②By using special techniques for signal enhancement,high-quality C13 nmr spectra may be obtained and these provide a useful complement to proton spectra.③In many substances a separate signal is observed for each carbon atom; and the chemical shifts are characteristic of particular structural types.Carbon signals are normally presented as singlets,but through a technique known as off-resonance decoupling they appear as multiplets in which the number of peaks is one more than the number of directly bonded hydrogens.③It is useful for determining the presence of certain functional groups based ontheir characteristic absorption frequencies.⑤By examining the fragments and by knowing how classes of molecules dissociateon electron impact,one can deduce the structure of a compound.Mass spectuometryis quite sensitive:as little as 10-9 g of compound is sufficient.生物碱Ground,air-dired,stem bark of O.glaberrima was extracted with CH2CL2/MEOH(1:1)at room temperature. The extract was concentrated under reduced pressure and its anti-microbial activities against a range -organisms were evaluated in vitro, using the agar diffusion test .Following bioassay-directed chromotographic fractionation ,two new alkaloid, oriciacridone A(1) and oriciacridoneB(2),were isolated , together with the known lichexanthone(3)Oriciacridone A (1) was obtained as yellow crystals and reacted positively with FeCl3, thereby indicating the presence of a phenolic hydroxyl group.何首乌理化鉴别Boil about 0.1g of the powder in 10ml of 10% sodium hydroxide solution for 3 min,cool and filter.Acidify the filtrate with hydrochloric acid,extract with equal quantity of ether, the layershows a yellow colour .To 4ml of ether solution add2ml ammonia TS,shake,the ammonia layer shows a red color.Heat under reflux about 0.2g of the powder in 5ml of ethanol for 5min,filter while hot,and allow to cool.Evaporate 2 drops of the filtrate to dryness in a porcelaindish ,add a drop of saturated solution of antimony trichlodide in chloroform ,a red-brown to violet-red colour is produced.（1）取粉末约0.1g，加10％氢氧化钠溶液10ml，煮沸3分钟，冷后滤过。