The code name of the first national standard material (NSM) is the code name of the first national standard material (NSM) with the prefix of "Guo", "Biao" and "Wu" in the Chinese pinyin of the NSM, which is represented by "GBW". First-class standard material, also known as the national first-class standard material, is a standard material approved by the national authority.

The number of a standard material is the standard material code "GBW" in the front of the number, the first two digits of the number are the major class number of the standard material, the third digit is the small class number of the standard material, the fourth and five digits are the serial number of the same class of standard material. The copy lot number is indicated in lowercase letters and is the last digit of the standard material number.

A standard substance is generally determined by absolute measurement or other accurate and reliable methods to determine the content of the substance, accurately set as the highest level in the country. The basic conditions of the national level standard substances stipulated by the State Bureau of Technical Supervision are:

1, the absolute measurement method or more than two different principles of accurate and reliable measurement methods for setting the value, but also by multiple laboratories with accurate and reliable methods to set the value;

2, the accuracy of the fixed value should have the highest level in China;

3, should have a national unified number of the standard material certificate;

4, the stability time should be more than 1 year;

5, the uniformity should be guaranteed within the accuracy range of a fixed value;

6, with the specified qualified packaging form. In general, the primary reference material should have an accuracy of 0.3-1%.

The above content is the introduction of the first level of standard substances, after reading the introduction of the above content, I believe that everyone will have a more in-depth understanding of the first level of standard substances. In our daily work, if we need to use standard substances, we can still make specific choices according to our actual needs.