Dry goods | hands on how to analyze infrared spectrum

Fourier transform infrared spectrometer (FTIR spectrometer) is short for Fourier transform infrared spectrometer It is different from the principle of dispersive infrared spectroscopy It is an infrared spectrometer based on the principle of Fourier transform of infrared light after interference It is mainly composed of infrared light source, diaphragm, interferometer (beam splitter, moving mirror, fixed mirror), sample chamber, detector, various infrared mirrors, laser, control circuit board and power supply It can be used for qualitative and quantitative analysis of samples, widely used in medicine and chemical industry, geology and mineral, petroleum, coal, environmental protection, customs, gem identification, criminal investigation identification and other fields Since its inception, infrared spectroscopy has been widely used in the study of organic chemistry In the 1970s, Fourier transform infrared spectroscopy (FTIR) technology entered the laboratory of modern chemists and became an important tool for structural analysis With the new features of high sensitivity, high resolution, fast scanning, on-line operation and high computerization, the classic infrared spectroscopy technology has been renewed Infrared spectroscopy is a common analytical method to identify compounds and determine the molecular structure of substances It can not only carry out qualitative analysis of substances, but also carry out quantitative analysis of components in a single component or mixture, especially for some samples which are difficult to be separated and can not find obvious characteristic peaks in the UV and visible areas, so it can be easily and quickly completed quantitative analysis Now infrared spectrometer is widely used in universities, colleges, research institutes, factories and mines for qualitative analysis of materials For example, infrared spectrometer can be used for compound identification, unknown compound structure analysis and compound quantitative analysis; chemical reaction dynamics, crystal change, phase change, material stretching and structure transient relationship research; continuous detection of industrial process and air pollution; monitoring of free silica in coal and carbon industry; detection of jewelry industry; measurement of crystal quartz hydroxyl Polymer composition analysis, drug analysis, etc Infrared spectrometer is also widely used in dyeing and weaving industry, environmental science, biology, material science, polymer chemistry, catalysis, coal structure research, petroleum industry, biomedicine, biochemistry, pharmacy, inorganic and coordination chemistry basic research, semiconductor materials, daily chemical industry and other research fields First, let's study or review the working principle of infrared spectrometer: due to the interaction between molecules and intramolecular, the characteristic frequency of organic functional groups will change slightly due to the different chemical environment of functional groups, which creates conditions for the research and characterization of intramolecular and intermolecular interaction Infrared spectroscopy can be used to study the structure and chemical bond of molecules, such as the determination of force constant and molecular symmetry, etc the bond length and bond angle of molecules can be measured by infrared spectroscopy, and the stereoscopic configuration of molecules can be inferred from this According to the force constants obtained, the strength of chemical bond can be deduced, and the thermodynamic function can be calculated from the normal frequency Some groups or chemical bonds in molecules are basically fixed or only changed in a small band Therefore, many organic functional groups such as methyl, methylene, carbonyl, cyano, hydroxy, amino, etc have characteristic absorption in the infrared spectrum Through the infrared spectrum measurement, people can The determination of which organic functional groups exist in the unknown samples lays a foundation for the final determination of the chemical structure of the unknown Many normal vibrations of molecules in the low wavenumber region often involve all atoms in the molecule Different molecules vibrate in different ways, which makes the infrared spectrometer have the same high characteristics as fingerprint, which is called fingerprint region Using this feature, we have collected the infrared spectra of thousands of known compounds, and stored them in a computer to compile a standard infrared spectrum library People only need to compare the infrared spectrum of the unknown with the spectrum of the standard library, then they can quickly determine the composition of the unknown compound With the development of modern infrared spectrometer technology, the significance of infrared spectrometer goes far beyond the stage of simple routine test of samples and inferring the composition of compounds A lot of new molecular spectral fields have been derived from the combination of infrared spectrometer and other testing methods For example, the combination of chromatography and infrared spectrometer creates an opportunity to deepen the understanding of the chemical structure of various components in complex mixture system; the combination of infrared spectrometer and microscope method forms infrared imaging technology, which is used to study the morphology and structure of heterogeneous system The characteristic bands of infrared spectrometer can be used to distinguish different compounds effectively, which makes the method have chemical contrast that other methods can not match After reviewing the above series of working principles and application cases of infrared chromatograph, we are going to do some dry goods In fact, many people have relevant summaries Here, we will give you benefits for free ~ ~ how to analyze infrared spectrogram? You are an expert after watching! docx, whether you remember it or not, download the collection first~~