Summary of shelf life knowledge of laboratory chemical reagents

Chemical reagents do not have a strict shelf life like food and drugs. Chemical reagents generally do not have specific requirements and boundaries for shelf life. According to national regulations, chemical reagents do not need to be labeled with a shelf life, and there is no shelf life to say. As long as their properties do not change, they can generally be used. Some reagents can be determined by whether they have clumped, weathered, deliquescent, or moldy to determine if they have expired.

According to the packaging standard for chemical reagents in GB15346-94 of the People's Republic of China:

Article 9.1.1. M stipulates that if it is required to indicate the validity period, it must be indicated; Production date or batch number.

2. Classification of chemical reagents in China:

Superior purity (GR, green label): the main component content is very high and the purity is very high, which is suitable for precise analysis and research work, and some can be used as primary standard.

Analytical purity (AR, red label): High main component content, high purity, and low interference impurities, suitable for industrial analysis and chemical experiments.

Chemical purity (CP, blue label): High content and purity of main components, with interference impurities, suitable for chemical experiments and synthesis preparation.

Experimental purity (LR, yellow label): High main component content, poor purity, no choice for impurity content, only suitable for general chemical experiments and synthesis preparation.

Indicators and colorants (ID or SR, purple label): Specific sensitivity is required.

Designated Level (ZD): Chemical reagents customized for specific users according to the quality control indicators required by the user.

Electronic purity (MOS): suitable for electronic product production, with extremely low content of electrical impurities.

Equivalent reagents (3N, 4N, 5N): The main component content is above 99.9%, 99.99%, and 99.999%, respectively.

3. Validity period of chemical reagents

Chemical reagents are subject to external factors such as temperature, light irradiation, air, and moisture during storage, transportation, and sales, which can easily cause physical and chemical changes such as deliquescence, mold growth, discoloration, polymerization, oxidation, volatilization, sublimation, and decomposition, making them ineffective and unusable. Therefore, it is necessary to use reasonable packaging, appropriate storage conditions, and transportation methods to ensure that chemical reagents do not deteriorate during storage, transportation, and sales. For those with special requirements for storage and transportation, special requirements should be followed. Some chemical reagents have a certain shelf life and must be used with caution.

The validity period of chemical reagents varies greatly depending on the chemical properties of the chemical. In general, substances with stable chemical properties have a longer shelf life and simpler storage conditions. To preliminarily determine the stability of a substance, the following principles can be followed:

Inorganic compound can be used for a long time as long as it is properly kept and its package is intact. However, substances that are prone to oxidation and deliquescence can only be stored for a short period of time (1-5 years) in a dark, shaded, and dry environment, depending on whether the packaging and storage conditions comply with regulations.

Organic small molecular weight compounds generally have strong volatility, and their packaging has good airtightness, which can last for a long time