The classification of chemical reagents in China is basically based on purity (impurity content), with a total of 7 types including high-purity, spectral purity, reference, spectral purity, superior purity, analytical, and chemical purity.

Common quality levels
Superior grade purity (GR, green label): also known as first grade or guaranteed reagent, 99.8%. This reagent has the highest purity and the lowest impurity content, and is suitable for important and precise analysis and scientific research work. Some can be used as reference materials.

Analytical purity (AR, red label): also known as secondary reagent, with high content of main components, high purity, 99.7%, low interference impurities, slightly inferior to superior grade, suitable for industrial analysis and chemical experiments, using red bottle labels.

Chemical purity (CP, blue label): also known as tertiary reagent, with high content of main components and high purity, ≥ 99.5%, containing interfering impurities, suitable for chemical experiments and synthetic preparation.
Experimental pure (LR, yellow label): also known as fourth grade reagent with high content of main components, poor purity, and no selection of impurity content. It is only suitable for general chemical experiments and synthetic preparation.
Indicators and dyes (ID or SR, purple label): require unique sensitivity.
Designated level (ZD): Chemical reagents customized for specific users based on quality control indicators required by the user.
Electron Pure (MOS): Suitable for electronic product production, with extremely low levels of electrical impurities.
Equivalent reagents (3N, 4N, 5N): The main component content is above 99.9%, 99.99%, and 99.999%, respectively.

In addition to the above levels, there are currently:
Primary reagent (PT): specifically used as a reference substance, it can be directly used to prepare standard solutions.

Spectrum pure reagent (SP): indicates spectral purity.
However, due to the inability of organic compounds to be displayed in the spectrum, sometimes the principal component cannot reach over 99.9%. Therefore, caution must be taken when using them, especially when used as reference materials, calibration must be carried out. Reagents with a purity much higher than that of high-grade purity are called high-purity reagents (≥ 99.99%).