Primary standards is of high purity, less impurity, good stability, chemical composition constant. Capacity analysis, the reference reagent in determination of pH in determination of calorific value, and so on. Have the first reference and classification standard of each classification. Where the first reference must be made by the National Institute of metrology verification. The production units used as the first reference standard benchmark products. At present, reference reagent business mainly refers to the capacity analysis in capacity analysis of benchmark [content range 99.95%~100.05% (gravimetric titration). Generally used to calibrate the titrant.
Antibiotics (Antibiotic), also known as antibiotics, is a variety of organisms (plant, animal and microorganism, especially soil microbial metabolic activities) products, is also capable of selectively inhibiting the microorganisms in low concentration, virus and properties of tissue cells. The antibiotic has grown to more than 2000, but the actual application not much. The chemical structure of different antibiotics, character, according to their chemical structure can be divided into 32 categories, such as nucleosides, peptides, proteins, macrolide, polyene macrolides etc.