Reference material occupies a very important position, and reference material has two main characteristics, such as uniformity and stability, among which reference material is often divided into certified and non-certified reference material. In fact, the reference material with a certificate is the certified reference material, and the natural non-certified reference material is the opposite. Although there are certain differences between the two, they all need to be verified, and the following Bolinda Xiaobian will introduce you to the verification of standard substances during the period.

In the daily management of standard substances, the most important thing is to develop a verification plan during the period and complete it on time. For the standard substances whose verification results do not meet the requirements of use or have expired, it is necessary to scrap them, fill in the verification and processing records related to the standard substances, and unify the summary and archiving.

There are also many methods for the verification of the standard material period, and several methods are recommended for your reference:

1, for unstable standard substances, try to buy small packaging, one-time use up, that is, try not to use unstable standard substances for a long time; No period verification required.

2. Comparison proof:

Purchase a new standard material and compare the quantity value with that which has been opened and used;

Send to a qualified testing or calibration institution for numerical confirmation;

Compare the quantity values between laboratories.

The samples that have recently participated in the capability verification and the results are satisfactory can be used as quality control samples in the stable period after participating in the capability verification;

Quality control chart is used to check the trend.

Period verification using synchronous stability method:

The self-configured standard reserve liquid or working liquid is divided into brown sample vial, half of which is stored at the reference low temperature and the other half at the conventional storage temperature. Samples at two temperatures are taken out at the same time before use, and the conventional storage samples are checked with the low temperature sample as the standard. A trial period report is obtained with the accumulation of data.

The expired standard material should be taken out and stored separately, and the newly configured standard material can be compared, and the deviation of the determination result should not exceed 10%, otherwise it should be scrapped.

The above content is the introduction of the period verification of standard substances, in recent years, with the in-depth development of CNAS laboratory accreditation, CNAS requirements for the period verification of standard substances are becoming more and more stringent. However, due to the lack of uniform norms or standards, laboratory technicians differ greatly in the understanding and implementation of period verification, especially in chemical analysis laboratories where standard substances are frequently used. In order to confirm the accuracy and reliability of standard substances, it is more necessary to study the method of period verification of standard substances.