Species of Chemical Reagent:

  There are many kinds of chemical reagents, and there is no uniform regulation on classification method in the world. Most countries are divided by application, such as General Reagents, analytical reagents, standard reagents, clinical chemical reagents, reagents used in the electronic industry and so on to dozens of categories, each category can also be divided into a number of subcategories. Chemical Reagents are also classified by composition, such as inorganic reagents, organic reagents, biochemical reagents, Isotopic labeling reagents, etc. . Each type of chemical reagents can also be divided into a number of subclasses, such as inorganic reagents can be divided into acid, Alkali, salt, oxides, such as simple substance. Organic reagents make up the largest category of ingredients (25,000, according to Feilac of West Germany) . In addition to the above two main classifications, chemical reagents can also be divided into high-purity reagents, high-grade pure reagents, analytical pure reagents, chemical pure reagents, and the purity of the label on the container so that the user can choose to use.

  High-purity reagents are often called ultra-pure reagents. The content of its main components should be close to the theoretical value (above 99.99%) , and its impurity content should be calculated by PPM and PPB. Emission spectroscopy, atomic absorption spectroscopy, polarography, chromatography, chemical analysis and other methods are commonly used to determine. High-purity reagents are commonly used in biochemistry, pharmaceutical research and trace analysis of physical chemistry. They are also used as functional materials in new industries such as microelectronics, semiconductors and optoelectronic communications (see reagents for the electronics industry) , such as ultra-pure gases.

Excellent pure reagent means the reagent with high content of main component and strict control of impurity content, such as excellent pure glacial acetic acid, the content of CH3COOH is above 99.8% (see table) . Mainly used for high precision analysis and measurement and experimental research.

  Analytical pure reagent refers to the reagent with high content of main component and lower control of impurity content than superior pure reagent. It can be used in analytical test and experimental research which require certain accuracy. For example, the content of CH3COOH in pure glacial acetic acid was above 99.0% .

 The impurity content of chemical pure reagent is slightly higher than that of analytical pure reagent. It can be used in general experiment and research. Due to preparation reasons, not every reagent has four kinds of purity products, and the index of each reagent is not necessarily the same. Many chemical reagents are toxic, flammable or explosive, use must be careful.