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【傅里叶红外检测的基本步骤】傅里叶红外检测的基本步骤及傅里叶红外测试原理

承天示优官方账号 2023-05-11 资讯 425 views 0

在化学分析领域,傅里叶变换红外光谱(FTIR)被广泛应用于物质成份和结构的鉴定。其使用非常普遍,因为它可以实现对各种样品进行快速、无损伤且高效率地检测。

傅里叶变换:

在讨论FTIR前,我们需要了解一下“傅里叶变换”这个概念。简单来说,这是一种数学工具,用于将时域信号(振动随时间而变化的图像)转换为频域信号(以不同频率分量组成)。因此,在处理复杂数据集时使用该方法很常见。

基本步骤:

1. 采集样品:

The first step in the FTIR testing process is sample collection. The sample can be in solid, liquid or gas form and must be representative of the material to be tested.

2. 加样:

The second step involves adding the sample to a suitable holder, such as KBr pellets or NaCl plates. It is important to select an appropriate holder that does not interfere with signal quality during measurement.

3. 生成光谱:

The third step is to generate the spectrum by passing infrared light through the sample and detector with an interferometer, which separates the beam into two paths. The difference between these paths generates a signal that is sent to a computer for analysis.

4. 数据处理:

The final step in FTIR testing involves data processing, where derived spectra are analyzed using specialized software tools. This can include peak identification, fingerprinting (a comparison of unknown samples with known standards), or other spectral calculations.

测试原理:

Infrared Radiation:

Infrared (IR) radiation refers to electromagnetic waves with frequencies ranging from 4000 to 400 cm-1 (wavelengths of about 2.5 microns to 25 microns). These wavelengths correspond roughly to the molecular vibrations of chemical bonds and are used in FTIR spectroscopy because they allow sensitive detection of changes in molecular structure or composition.

Interferometry:

A typical interferometer consists of an IR source, two mirrors placed at right angles reflecting perpendicular beams onto a single point, and eventually through a sample cell before the signal reaches a detector such as mercury cadmium telluride or deuterated triglycine sulfate.

In FTIR spectroscopy, an interferogram is produced when monochromatic light passes through both halves of a beam splitter – one half directed towards reference mirror; another half passed through sample material before reaching a detector. Fourier transform is used to convert the interferogram into more useful information that can be displayed on a spectrum.

Spectral Interpretation:

Once the FTIR has generated an absorbance spectrum, it is important to interpret this data correctly. Sometimes spectral interpretation merely involves identifying characteristic absorption bands and correlating them with known functional groups present in common organic compounds.

结论:

傅里叶变换红外光谱技术提供了一个快速、无损伤且高效率的分析工具,使化学家能够轻松地识别和鉴定各种样品。这个过程包括采集样品,加样并通过干涉仪获取光谱。得到的数据可用于指纹比较和其他计算中。

In addition, IR radiation allows for sensitive detection of changes in molecular structure or composition, providing valuable information about chemical properties and potential interactions. Ultimately, FTIR testing is an essential technique that helps advance scientific research across many fields and industries.

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