拉曼光谱技术在宝石学研究中的应用

拉曼光谱技术已被成功地应用于宝石学研究和宝石鉴定领域。拉曼光谱技术可以准确地鉴定宝石内部的包裹体,提供宝石的成因及产地信息,并且可以有效、快速、无损和准确地鉴定宝石的类别——天然宝石、人工合成宝石和优化处理宝石。但是,该技术也存在着一定的局限性。     

拉曼光谱在宝玉石鉴定中的应用

:利用拉曼光谱鉴定宝石越来越受到宝石学界的关注。本文测定了许多宝石的拉曼光谱 ,其中包括宝石、玉石、人造宝石和一些贵重宝石的代用品。这些谱图可以作为宝石鉴定的标准对照谱。文中还讨论了宝石拉曼光谱鉴定的一些特点     

仿宝石塑料材料的拉曼光谱分析

应用便携式拉曼光谱仪对赛璐珞、聚苯乙烯、聚氯乙烯、聚甲基丙烯酸甲酯这4种较为常见的仿宝石塑料材料进行了分析测试研究,获得它们的标准拉曼光谱.然后将它们与其对应的被仿宝石(象牙、琥珀、珍珠、水晶)的拉曼光谱分别进行了比对分析.研究结果表明,因其分子结构存在较大差异,其拉曼光谱的差异也比较显著,从拉曼光谱上就能准确地将它们辨别出来.从而找到了一种便捷、准确、快速、无损的鉴定宝石与其塑料仿品的方法.     

显微拉曼光谱在宝石鉴定中的应用

探讨了用显微共焦拉曼光谱仪鉴定宝石的可行性、可靠性。结果表明,根据对宝石本体的拉曼测量很容易识别真假宝石。而用显微共焦系统对微小包裹的测量可提供宝石是天然或人造的信息,甚至可追踪天然宝石的产地。我们还注意到,与拉曼谱同时记录到的光荧光谱也是有关样品的珍贵信息,有时也可据此判明宝石是天然的还是人工合成的     

琥珀、柯巴树脂、松香的光谱学特征

应用常规测试手段、紫外可见光谱、红外光谱和拉曼光谱分别对天然琥珀、柯巴树脂、松香进行了测试.研究结果表明:柯巴树脂的拉曼光谱出现的932、964cm-1和989cm-13处及1179cm-1、1226cm-1和1266cm-1 3处的特征振动峰,是首次运用拉曼光谱技术证实柯巴树脂中萜烯类化合物存在的有力证据,而这些特征峰在天然琥珀的拉曼光谱中没有出现;松香的拉曼光谱存在1589cm-1的特征振动峰,是由其内部的不饱和树脂酸中的共轭双键所致,这正是松香和天然琥珀的特征区别依据,从而分别解决了目前琥珀的天然树脂类高仿品的鉴别难点.因此应用拉曼光谱技术对有机宝石琥珀及其天然树脂类高仿品进行鉴定和分析具有较大的优势和便利.     

拉曼光谱技术在食品质量安全检测中的应用

拉曼光谱技术具有样品无需前处理、操作简便、时间短、灵敏度高等优点,可获得样品的物理化学及深层结构信息,已广泛应用于石油化工、生物医学、地质考古、刑事司法、宝石鉴定等领域。拉曼光谱对水等极性物质极其不敏感,在食品质量安全检测方面具有良好的应用前景。论文简述了拉曼光谱技术的检测原理、分类以及系统的组成,综述了拉曼光谱技术在食品成分分析和农药残留检测中的最新研究进展,指出了该技术在食品质量安全检测中的关键技术并对今后的研究进行了展望。     

天然、合成红宝石的拉曼光谱分析

天然与合成宝石一直是宝石鉴定中的难题,而拉曼光谱的半高宽,即声子"寿命"可提供宝石是天然或合成的信息。论文利用BTR111-785微型近红外拉曼光谱仪对天然、合成红宝石进行测试分析,研究表明天然红宝石的半高宽均在10cm-1以上,合成红宝石的半高宽均低于10cm-1。     

红外光谱技术在翡翠鉴定中的应用

在翡翠贸易中,鉴定天然翡翠和处理翡翠是一个非常重要的问题。传统的翡翠鉴定方法,主要依赖于折射仪、宝石显微镜、滤色镜和分光镜进行检测,而所有这些方法对于鉴定处理翡翠。这种方法不仅可以鉴定未镶嵌的翡翠,而且还可以鉴定镶嵌翡翠和一些大型的翡翠饷品,如手镯、挂件和串珠等。     

应用振动光谱技术检测鉴定微生物的研究进展

振动光谱（红外光谱和拉曼光谱）技术与化学计量学相结合的方法对微生物进行分类、鉴定和无损检测,该方法快速简便、准确度高、仅需微量样品和少量化学试剂、对样品本身没有损害。介绍了振动光谱技术在微生物鉴定检测中的工作原理、关键技术和应用,并对该方法存在的问题和研究前景进行了分析和展望。     

一些天然、合成及仿造宝石的显微拉曼光谱鉴别

本文主要测定部分天然宝石、合成宝石以及仿造宝石 ,以期建立云南宝玉石拉曼光谱数据库 ,进而为鉴别宝石的合成品、仿造品提供标准谱图     

Raman Spectrum of n-Propylamine in Cyclohexane

Polarized (Isotropic) Raman spectra of the N-H valence region of n-propylamine have been recorded as a function of concentration in cyclohexane. Statistical analysis of the data using non-linear least squares techniques revealed the presence of a fourth spectral band in this region, not observed in an earlier IR study. This latter peak has been assigned to vibrations of monomers in the liquid. The resolved spectral parameters are consistent with a picture of diminishing molecular association upon dilution of the amine in this non-polar solvent.     

拉曼光纤技术快速无损鉴别甲硝唑片

采用光纤探头直接放在甲硝唑片上进行检测,采集谱图,对拉曼光谱峰进行指认,并改变测定条件(药品隔铝塑包装、刮除包膜)进行测定。建立了光纤传感技术结合拉曼光谱快速无损鉴别甲硝唑片的方法,所测药物图谱峰形良好、峰强明显、指纹性强、测定快速准确,可瞬间获得片剂的特征图谱。样品无需进行前处理,可无损鉴别。药片检测时,是否隔铝塑包装和刮除包膜不影响谱图识别。本法快速、准确、专属性强、灵敏度高,可用于对甲硝唑片进行有效的鉴别。     

翡翠B货的拉曼光谱鉴别

与传统宝石鉴定相比 ,拉曼光谱在漂白或注胶翡翠 (B货翡翠 )的鉴别中是一种快速、无损、微区分析方法 ,特别对于宝石中的包体和填充物尤其有效[1 ] 。翡翠中经常充填各种油、蜡、胶 (如石蜡、石蜡油、AB胶、环氧树脂等 )来增强其透明度[2 ] ,由于它们化学成分、化学结构的不同 ,在拉曼光谱中显示不同的峰位特征。环氧树脂的特征峰主要属于苯环的 :1 60 9和 1 1 1 6cm- 1 两个C—C伸缩振动 ,3 0 69cm- 1 C—H的伸缩振动以及 1 1 89cm- 1 C—H的面内弯曲振动 ,而用于翡翠抛光处理的石蜡不具有苯环的特征峰 ,据此可作为鉴别B货翡翠的依据。     

Diffuse Reflectance Spectra of Rare Earth Benzoylacetonates in Ultraviolet region

Rare earth β-diketonates are promising laser materials. Their solid state spectra is expected to give their spectral characteristics. The diffuse reflectance spectra of some rare earth β-diketonates and esters in ultraviolet region have been reported recently by the authors¹. The ultraviolet absorption spectra of transition metal chelates have also been reported^2,3 recently. The spectra of the non-transition metal ion chelates usually consist⁴ only of the metal charge transfer and ligand intramolecular transitions. The ligand transitions in all the cases are characteristic of the coordinated ligand. The spectrum of the ligand, however, helps in assigning the transitions of the co-ordinated ligand. A comparison of the spectrum of ligands and their rare earth complexes^1,5,6 shows that on complexation no new bands appear in ultraviolet suggesting that unlike transition metal β-diketonates^2,3, charge transfer bands do not appear in the present case. The ligand intramolecular transitions are expected mainly due to the carbonyl group.     

A PCA study to determine how features in meteorite reflectance spectra vary with the samples’ physical properties

Meteorites have advanced our knowledge of processes in the Solar System with the application of high precision instruments here on Earth. The study of asteroids, the source of most meteorites, has in turn given us knowledge regarding the large scale evolution of the Solar System. Using the complementary information that asteroids and meteorites give us the story of our cosmic backyard can be more easily read. One efficient way to link meteorites to asteroids is by matching their respective reflectance spectra. There have been few convincing matches because of observational and scale differences as well as an incomplete knowledge of the light scattering physics involved. To better interpret the reflectance data we need to know the dependencies of the reflectance on physical properties and develop techniques for better comparisons of data sets. For these purposes we utilise our own measurements of 26 different meteorites together with spectra available on the NASA PDS.We find that normalisation of reflectance at a wavelength between 1.1 and 1.3 μm gives the closest match of spectra from meteorites common to both data sets. The depth of the spectra bands deepens by similar amounts for different types of surface texture alterations i.e. rock to sawn surface, rock to polished surface and rock to powdered surface. Principal Component Analysis (PCA) is able to easily place carbonaceous chondrites, ordinary chondrites and achondrites into distinct groups using their reflectance spectra. We track the variation of spectral features in principal component space by using a set of meteorite spectra synthesised from mineral and elemental spectra. A spectral agent that reduces the reflectance at all wavelengths is required, in addition to olivine, pyroxene and carbon, to generate a set of synthesised spectra to match the distribution of measured spectra, in principal component space.     

高纯度烟草过氧化物酶（TOP I）光谱特性研究

采用交换吸附脱色及柱层析新技术，成功地从烟叶中分离和纯化了一种烟草过氧化物酶同工酶(TOP I)，并对其进行了一系列光谱特性研究。基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)测得TOP I分子量为21888．5，等电点pI为3．5；氨基酸组成分析表明TOP I为一含血红素的酸性蛋白酶。光谱学分析揭示，在402nm处有一典型的Soret带，在498和636nm处有特征吸收峰(α，β带)，酸度和变性剂对TOP I在紫外可见区的特征吸收峰均产生一定的影响，TOP I的荧光光谱测定结果说明TOP I分子中含有Trp残基和Tyr残基以及其自身的独特的光谱学特性。     

Coherent X-Ray Scatter for Identifiction of Explosives

Coherent X-ray scattering spectra of some explosives (black powder, TNT, etc.) and some non-explosives (sugar, milk powder, coffee, paper, etc.) have been measured using polychromatic X-rays (1.2—38.2KeV) on Beijing Synchrotron Radiation Facility of IHEP Beijing. The measured peak positions of X-ray diffraction spectra can be regarded as a 'fingerprint' of the explosives. Principally, peak positions and identification techniques of diffraction spectra can be used for the identification of explosives.     

傅里叶红外(FT-IR)差谱技术在复合材料分析中的应用

用FT-IR差谱技术对几种类型的复合材料进行定性分析，尝试能有效地找出影响分析结果的某些因素，从而提高应用该技术分析的效果。通过实例表明，该技术是一种值得推荐的快速鉴定方法。     

Spectral Investigation of Neodymium and Praseodymium Nitrobenzoic Acid Complexes in the Region 4000-250 cm−1

The infrared absorption spectra of acetylacetonates of divalent ions^1,2 of Co, Ni, Cu and Pd; trivalent ions³ of Al, Fe, Mn and Cr and tetravalent ions^4,5 of Zr and Hf have been studied, but very little work has been reported in case of aromatic acid complexes of rare-earth metals. Consequently, it was thought worthwhile to carry out present investigation to obtain a detailed information about the geometry of the molecule and the nature of the metal-oxygen bond in the complexes. The present communication reports the infrared absorption spectra of the complexes of p-nitro benzoic acid with Nd³⁺ and Pr³⁺ metals, presumably for the first time. The results have been discussed on the basis of theoretically calculated different modes of vibration. An attempt has been made to investigate the nature of metal-oxygen bonding in the complexes.