To initially determine the stability of a substance, the following principles can be followed:
Inorganic compounds can be used for a long time as long as they are properly stored and packaged intact. However, those substances that are easily oxidized and deliquescent can be stored in a short period of time (1 to 5 years) in the dark, shade, and dry conditions, depending on whether the packaging and storage conditions are in compliance.
Organic small molecular weight compounds generally have high volatility, and the packaging has good airtightness and can be stored for a long time. However, it is easily oxidized, decomposed by heat, easily polymerized, and photosensitive.
Organic polymers, especially life materials such as oils, polysaccharides, proteins, enzymes, and peptides, are highly susceptible to microbial, temperature, and light, and lose their activity, or become spoiled. Therefore, they must be refrigerated (frozen) and stored. Shorter.
In principle, the reference materials, reference materials and high-purity substances should be stored in strict accordance with the preservation regulations to ensure that the packaging is intact and protected from the chemical environment, and the storage time should not be too long. In general, the reference substance must be used within the validity period.
The stability of most chemicals is still good, and the specific conditions are determined by actual use requirements. If the analytical data is generally understood, or there are no specific requirements for the analytical results, such as general teaching experiments, the quality level of the chemical reagents can be used as a general requirement. However, factory test data is used to guide production, and the quality index of chemical reagents must not be vague. Chemical reagents used in general synthetic preparations are, in most cases, industrial grade chemical reagents. However, the research type and the synthesis of certain specialty chemicals, in some cases, the quality requirements of raw materials are very strict and need to be strictly controlled.
In the actual use process, people are always accustomed to using the date of production to judge the effectiveness of chemical reagents, in fact, it is not the case. For example, in a college or university, it has been seen that warehouse managers have cleared all chemical reagents that have been in the factory for more than two years and are ready to destroy, on the grounds that they have expired. Not to mention the huge waste of funds, it is enough to deter the chemical dangerous goods destruction program. What's more, it is not allowed to buy commercial companies, in case the merchants "deceive people", their feelings are sigh, the situation is sad! Later, it was said that these large quantities of chemical reagents were buried in the deep hole.
In short, the effectiveness of chemical reagents must first be based on the physical and chemical properties of the chemical reagents, and then the apparent observation of the chemical reagents, and then based on the specific needs to make a conclusion.
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