The European Union put forward the REACH regulations in June 2007 for the registration, evaluation, authorization and restriction of chemicals. The aim of this resolution was to raise the levels of protection of human health and the environment from harmful chemicals and to delegate the responsibility of understanding and managing the associated risks to chemical importers and manufacturers.
根据《覆盖范围法规》，进口商和制造商需要在欧洲化学局（ECHA）中注册物质。注册过程涉及一组详细的分析数据，以验证材料身份。亚博网站下载
Tests such as FTIR, NMR, UV-VIS and mass spectroscopy to determine molecular structures and LC or GC tests for assessing impurities are the basic requirements of the ECHA. Some special cases may require additional processes like X-ray fluorescence or X-ray diffraction.
Although it seems like a simple procedure to characterize solids and liquids as per the ECHA norms, the characterization of gases tends to be problematic as most of these techniques are not useful for the majority of gases. Techniques like mass spectroscopy, GC and FTIR are suitable for certain gases, but techniques like NMR spectroscopy are not. Substantial information can be obtained by UV-VIS spectroscopy only in the case of gases that contain strong chromophores.
The concern about rejection of applications by the ECHA based on just these three analytical techniques is increasing, which in turn triggers the need for alternative approaches towards characterization of gases.
潜在的替代技术之一是拉曼光谱法由于它可以鉴定出对红外辐射的无活性的同核双原子学。拉曼光谱学还提供了类似于FTIR光谱的信息，但是互补的，这是一种接纳的注册技术。
Raman Measurement of Gases
由于在大气压下样品中分子的数量较低，因此从蒸气或气体获得的拉曼散射通常很弱。为了从短时标准的气体中获取高质量的数据，可以使用新的探针设计，例如Kaiser Airhead™。
在此实验中，空头探针与Kaiser RamanRxn Systems™ analyzer它配备了100 mW 532 nm二极管的ND：YAG激光器和毛皮冷却的CCD检测器。该实验的样品处理系统如图1所示。使用拉曼光谱进行分析，并在气体处理线中与电池进行现场进行分析。
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Figure 1.气体处理系统的示意图。
示例ch4/H2混合物
The spectrum obtained from a methane sample containing around 1% hydrogen is shown in Figure 2. It can be seen from the spectrum that strong, sharp rovibrational band patterns between the 3000 and 1500 cm-1区域是甲烷气体的典型指纹。
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Figure 2.拉曼光谱为1％h2英寸4。The sharp bands below 1040cm-1是H的纯旋转过渡2分子。
h2stretching vibration is represented by the single band near 4159 cm-1。Due to the absence of a H2振动期间偶极矩这种模式在红外光谱中不活跃。在这种情况下，即使FTIR光谱法（这是ECHA要求用于振动光谱法要求的默认技术）能够检测甲烷，因此为材料组成所提供的数据具有误导性，因为它不考虑氢成分。
h2拉伸带显示为1040厘米之间的一系列不同的带-1and 350 cm-1，代表H的纯旋转过渡2分子。其他物种在较低的波数中表现出这种转变，因为H2is comparatively lower. Detection of H2at such low concentrations (1%) in CH4变得困难。拉曼光谱能够通过启用具有气相能力的技术来克服当前分析技术的局限性，以定量测量同核双原子学。
示例：异丁烯和丁二烯
两个不饱和C样品的拉曼光谱4gases obtained by the averaging of six scans of 30 second duration is shown in Figure 3.
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Figure 3.拉曼光谱4气体。上部迹线与异丁基一致。较低的迹线由于丁二烯而具有很强的带，并且由于异丁基而引起的几个较弱的带（箭头）。
The upper blue trace in the spectrum emitted by the first sample corresponds to isobutylene. The second sample emits the lower trace corresponding to butadiene. In addition to the two main traces, there are numerous weak bands which are marked as vertical rows confirming the low concentration of isobutylene.
其他气体
图4显示了其他三个烃类样品的光谱，这表明了空头探针对简单气体的一般分析的适用性。这三个光谱代表了持续30秒的六次扫描的平均值。上部和中部区域的痕迹分别对应于丙烷和n-丁烷，而下部迹线是丙烯具有较小的丙烷杂质。
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图4。三种常见碳氢化合物气体的Airhead™光谱。一个弱带附近870厘米-1暗示丙烯中有轻微的丙烷杂质。
结论
能力gases to instantly yield high-quality Raman spectra is demonstrated by these examples. The distinct finger print provided by the Raman spectrum is useful to validate molecular structures and in the quantitative analysis of mixtures. Comprehensive characterization of a sample can be carried out by combining IR and Raman spectroscopy, since both of them are subject to different selection criteria.
单独使用这两种技术中的任何一种都可以提供分子组成的误导性结果。能力Raman spectroscopic methods本文证明了在检测和定量中，IR技术无法通过IR技术访问。除此之外，还证明了拉曼光谱在满足固体和液体的满足登记处的有效性。
此信息已从Kaiser Optical Systems，Inc.提供的材料中采购，审查和改编。亚博网站下载
有关此消息来源的更多信息，请访问Kaiser Optical Systems，Inc。。