Comprehensive overview of the functions and analysis features of 22 analytical instruments

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Comprehensive overview of the functions and features of various analytical instruments. Instrumental analysis: Instrumental analysis is a term that refers to a variety of analysis methods characterized by the use of relatively complex instrumental devices. Due to its advantages such as high sensitivity, fast speed, good selectivity, and the ability to enable automatic recording and continuous measurement, it has gradually become the mainstream in chemical analysis. The most common instrumental analysis methods are as follows: Emission spectroscopy analyzes the chemical composition of a substance based on the spectrum generated by its excitation to emit light. Spectroscopic methods with different names, using various excitation sources. If high-frequency inductively coupled plasma (ICP) is used as the excitation source, it is called high-frequency inductively coupled plasma emission spectroscopy ； When a laser is used as the light source, it is called laser probe microanalysis. 　　Atomic absorption spectroscopy relies on the characteristic spectrum of the element to be analyzed; the gaseous atoms of that element in the vapor absorb light, and by measuring the degree of weakening of the spectral lines (absorbance), the concentration of the element in the sample can be determined. The more widely used methods are flame atomic absorption and non-flame atomic absorption; the latter has a sensitivity 4 to 5 orders of magnitude higher than that of the former. 　　Atomic fluorescence spectrophotometry determines the element of interest by measuring the intensity of the fluorescent emission produced by its atomic vapor when excited by radiant energy. 　　Infrared absorption spectroscopy is primarily used to determine the composition of organic compounds, identify their chemical structures, and conduct quantitative analysis; in recent years, it has also been applied to inorganic compounds. 　　UV-Vis spectrophotometry is suitable for the determination of components with low concentrations, and it can also be used for the analysis of multi-component mixtures. Catalytic reactions can be used to **improve the sensitivity of this method. 　　Fluorescence spectrophotometry exhibits high sensitivity and selectivity for certain elements. 　　Infrared Fourier transform spectroscopy involves feeding optical signals into a computer in the form of interference patterns for mathematical Fourier transform processing, and it features a high signal-to-noise ratio and high sensitivity. 　　Nuclear magnetic resonance spectroscopy is used to identify organic compounds and the components of multi-component mixtures, as well as to analyze the molecular structure of inorganic substances, by utilizing the proton resonance of organic molecules. 　　Electron spin resonance is an analytical method based on the splitting of magnetic energy levels caused by the effect of a magnetic field on the unpaired electrons in ions, molecules, or atoms. 　　Raman spectroscopy can be used to determine molecular structure. Raman spectrometers equipped with tunable lasers are employed for trace analysis, as well as for the structural analysis of inorganic substances and single crystals. 　　X-ray fluorescence spectroscopy has advantages such as simple spectral lines, low matrix effect, high selectivity, and a wide measurement range. Non-destructive analysis can be performed on all elements with an atomic number greater than 9. 　　Electron probe microanalysis can analyze all elements with an atomic number greater than 4; it is used for the analysis of particulate minerals and rocks, the distribution of elements in metal materials, and the allocation of elements within various phases. 　　Electron spectroscopy is a method for determining electron binding energy; it is a powerful tool for studying surface chemistry and can be used for the qualitative analysis of any element other than H and He. 　　Auger electron spectroscopy is used to analyze the composition, valence states, and structure of inorganic and organic samples, and it is generally a non-destructive analysis method. 　　Radiochemical analysis includes neutron activation methods, photon activation methods, charged particle activation analysis methods, etc. 　　Müsler spectroscopy targets individual nuclei and can be used to study the effect of impurity atoms and vacancies in materials on their properties. 　　Mass spectrometry possesses high discrimination and detection capabilities, and can analyze all elements. Spark source mass spectrometry is suitable for determining trace elements. 　　Ion probe microanalysis: The area of analysis is approximately 1–5 μm in diameter and several dozen angstroms in depth; it enables scanning analysis and can detect almost all elements. 　　Potentiometry is a method that relies on the changes in cathode (or anode) polarization. It is characterized by high sensitivity and a low amount of sample required, enabling the detection of substances with extremely low concentrations. 　　The ion-selective electrode method is an indicator electrode that uses potentiometry to measure the activity of a specific ion in a solution, enabling rapid, continuous, and non-destructive selective detection of the activity of certain ions in the solution. 　　Coulometric analysis includes potentiostatic coulometric analysis and constant-current coulometric titration. 　　Chromatography is a separation analysis technique that utilizes the differences in the solubility, distribution, adsorption, desorption, or other affinity properties of various components within a mixture in different phases to separate them from one another. Based on the state of the mobile phase, it can be divided into gas chromatography and liquid chromatography; based on the form in which the stationary phase is used, it can be divided into column chromatography, paper chromatography, and thin-layer chromatography.