What Is Qualitative Analytical Chemistry?

Chemical analysis refers to the method of determining the chemical composition or composition of a substance. It can be divided into inorganic analysis and organic analysis according to the properties of the analyzed substance. According to the requirements of analysis, it can be divided into qualitative analysis and quantitative analysis. According to the number of analytes, it can be divided into constant analysis, semi-micro analysis, micro analysis and ultra-micro analysis. Industrial raw materials, semi-finished products, finished products, agricultural soils, fertilizers, feeds, and transportation fuels and lubricants all require chemical analysis in the process of research, trial production, production or use. ^[1]

Analytical chemistry is the main basic course for undergraduates, including "quantitative chemical analysis" theory courses, qualitative chemical analysis, basic chemistry experiment courses, "instrument analysis" theory courses, and experimental courses. The courses are offered to undergraduates majoring in chemistry and biology, medicine and geoscience. Analytical chemistry has a strong practicality, and at the same time has a rigorous and systematic theory. It is a discipline that closely combines theory with practice. Studying analytical chemistry is conducive to cultivating students' rigorous scientific attitude and realistic style, so that students can initially master the skills of scientific research and initially have the comprehensive quality of scientific research. Analytical chemistry covers a wide range of topics and is developing very rapidly. While teaching basic theories, try to intersperse some examples of using basic theories to solve practical problems, including new progress and new results in analytical chemistry in various fields such as medicine, environment, and biology. Maintain the systematic nature of chemical analysis theory and continuously enrich new content, keep

When the knowledge of inorganic chemistry was gradually systematized in the 19th century, the invention and use of J & ouml; ns Jakob Berzelius analytical balances made the measured experimental data closer to the true value, so that any one law has a conclusive It turns out. Berezeus has introduced many new methods, new reagents, and new instruments for the determination of atomic weight into analytical chemistry, bringing the accuracy of quantitative analysis to a new level. Later, he was respected as the father of analytical chemistry.

In terms of qualitative analysis, the German chemist Hoinrich Rose wrote a "Analytical Chemistry Course" in 1829, and for the first time proposed a systematic qualitative analysis method, which is basically the same as the current general analysis method. By the end of the 18th century, various forms and principles of acid-base titration were basically determined. For an important part of analytical chemistry, spectral analysis began with Newton. Newton began to study spectra in 1666, and published his first paper "New Theory of Light and Color" in 1672.

Chemical analysis can be divided into titration analysis and gravimetry according to different operation methods.

Instrumental analysis methods: Analytical methods based on the physical and physicochemical properties of substances are called physical and physicochemical analysis methods. This type of method requires a special instrument, which is often called an instrumental analysis method. The main instrumental analysis methods are as follows:

1.Optical analysis method

An analytical method based on the optical properties of a substance. It mainly includes: molecular spectroscopy, spectroscopic analysis, molecular fluorescence and phosphorescence analysis; atomic spectroscopy, such as atomic emission spectroscopy and atomic absorption spectroscopy.

2.Electrochemical analysis

An analytical method based on the electrochemical properties of a substance. It mainly includes potential analysis, polarography and voltammetry, electrical weight and coulomb analysis, and conductance analysis.

3.Chromatographic analysis

A separation and determination method based on the difference in the adsorption capacity, partition coefficient, or other affinity of two substances (stationary and mobile). The biggest feature of this analysis method is the integration of separation and determination, which is an efficient, fast and sensitive analysis method for multi-component substances. It mainly includes gas chromatography and liquid chromatography. ^[2]