Tens of thousands of kinds of chemical reagents (chemical Regent) product is relative standard substance of chemical research, component analysis, is an important condition for the progress of science and technology, are widely used in the physical synthesis, separation, qualitative and quantitative analysis, can be said to be chemists eyes, in factories, schools, hospitals and research institutes of the daily work, are inseparable from the chemical reagents. It is usually divided into three categories: inorganic chemicals, organic chemicals and biochemical reagents. But all kinds of chemical reagents because of the purity, impurity content, use, etc., and there are many levels.
　　Domestic chemical reagents are generally divided into four levels according to the amount of impurities:
　　One, LR reagent:
　　Laboratory reagent, the agent, four agents, abbreviated as LR.
　　Two, CP reagent:
　　Chemical pure, chemical reagent, reagent grade three, abbreviated as CP, with dark blue label on the bottle.
　　Three, AR reagent:
　　Analytial reagent, analytical reagent two, reagent, abbreviated as AR, with a red label general bottle.
　　Four, GR reagent:
　　Guaranteed reagent GR reagent, also known as guaranteed reagent, a reagent grade, abbreviated as GR, glass bottle with a green label.
　　In addition to the above four commonly used level, the current market is still:
　　Reference reagent:
　　Primary reagent, abbreviated as PT. The standard solution can be directly formulated and used exclusively as a reference material.
　　Spectral pure reagent:
　　Spectrum pure, abbreviated as SP pure spectral representation. However, due to the organic matter in the spectrum can not be displayed, so sometimes the main component of less than 99.9%, the use must pay attention to, especially when the benchmark must be calibrated.
　　Main use of chemical reagents at various levels:
　　GR:Guaranteed reagent, gr. The content of the main component is very high, the purity is very high, it is suitable for the precise analysis and research work, and some can be used as reference material.
　　Reagent AR:Analytial, analysis of pure. The content of the main component is very high, the purity is high, the interference impurity is very low, and it is suitable for industrial analysis and chemical experiment.
　　Pure CP:Chemical, chemical purity. The content of the main component is high, the purity is high, and the interference impurity exists, which is suitable for the preparation of chemical experiment and synthesis.
　　Reagent LR:Laboratory, experimental pure. The content of the main component is high, the purity is poor, and the impurity content is not selected, which is only applicable to the general chemical experiment and synthesis process.
　　Reagent BR:Biological, biochemical reagent. For the preparation of biochemistry test, and biochemical synthesis. Quality indicators focus on biologically active impurities. Alternative indicators and organic synthesis.
　　Stain BS:Biological, biological stain. Suitable for preparation of biological specimens staining solution. Quality indicators focus on biologically active impurities. Alternative indicators and organic synthesis.
　　Ind:Indicator, color rendering agent.
　　Performance liquid chromatography HPLC:High, high performance liquid chromatography, suitable for high pressure liquid chromatography reagents.
　　Classification of imported chemical reagents:
　　Pure Ultra: ultra pure, similar to the GR class.
　　Purity High: high purity, similar to the AR level.
　　Biotech: biological technology level, similar to the BR level.
　　Reagent: reagent grade, similar to CP level.
　　ACS: the American Chemical Society standard, similar to the AR class.
　　USP: pharmaceutical grade.