I believe that many laboratories have encountered such an embarrassing situation: the standard expired, throwing or not throwing? In accordance with the requirements of CNAS accreditation guidelines, expired standards cannot be used for testing related to test result reports. But there are always a few standard products, the price is very expensive, but can not use a few times expired, if the standard expired, it can be used as waste? Below, Bolinda Xiaobian to introduce how to use waste when the standard product is expired.

Some netizens said that it is completely ok to do qualitative analysis and rapid screening of pesticides. For example, for the study of pesticide metabolism, general analysis can be used if it does not require too accurate quantification.

In fact, laboratories that do residual have more or less expired standards, mainly because it is more difficult to use up all of them within the shelf life.

There are even predecessors with expired standards to do comparative experiments, data show that if the standard is properly stored, after the shelf life does not affect its use, and even one year after the expiration of the quantitative accuracy is not affected.

In general, if the standard is out of date, we can use these methods:

1, as waste liquid or solid waste unified classification treatment, used for internal quality control.

2, the expired standard sample for a check, with the newly purchased standard liquid to quantify (please pay attention to cost considerations), refer to the physical and chemical properties of the standard product, as long as the change is not large, can be used as a recovery test.

3, can be used for the study of the change law of standard products, under the premise of extremely weak response of degradation products, used for peak characterization of chromatographic analysis.

4. It can be used for internal quality control, data comparison as blind samples, qualitative analysis and rapid screening of pesticides, exploration of experimental conditions and optimization of parameters in the laboratory.

Some of the above tips are for the laboratory cost consideration of waste utilization, for the regular CNAS certification laboratory, only in accordance with the regulations, due to replace, this obvious management loopholes can not have.

The above content is the introduction of how to use waste when the standard is expired. If there are no special circumstances, the content of the working standard is re-marked once every six months or another newly produced sample is calibrated. When the standard product is not used temporarily, the re-marking cycle may exceed the specified period, and the re-marking is carried out before use, and it can continue to be used after passing