634751797512815000.jpg

The standard has expired, how can I know if it is still valid?
There are no expiration dates for the USP. For many, it can be used for statutory applications as long as it is listed as "current batch" by the current (latest) USP legal directory. Once removed from the current batch, the batch will be listed in the “Previous Batch” directory and the “Validity Period” will appear. The last day of the month shown is the expiration date for the batch.
The electronic version of the legal USP catalogue is published every two months and the printed version is published every four months. The daily USP catalog is updated daily. The user is solely responsible for determining that a particular USP is in a statutory state, that is, not a "current batch" or a "previous batch" with a validity period.

标准品11.jpg

Classification of standard products:
·Classified by technical characteristics
Chemical constituent standard substance
Such standard materials have a defined chemical composition and are accurately metered in a chemically correct manner for the calibration and analytical methods of the component analysis instrument.
2. Physical and chemical properties Standard materials These standard materials have some good physical and chemical properties and have been accurately measured for the calibration of calibration methods or measurement methods for physical and chemical properties measuring instruments.
3. Engineering technical characteristics Standard substances These standard materials have certain good technical characteristics and are accurately measured. They are used for calibration of engineering technical parameters and characteristic measuring instruments, evaluation of measuring methods, and comparative measurement of materials or product technical parameters.
·Classified by subject or profession

Can be divided into geological, physical and chemical, etc., Iso used this method to compile the standard substance guide.

Shanghai Hengyuan Bio-study promotion and new product supply are in progress at the same time. Consulting and ordering our company's standard products can: 1 Leave us a message on this website; 2 Call us directly for our salesman.

Office Staples

Office Staples,Staples Coupons,Staples Hyken,Staples Binders

SHAOXING YIYOU STATIONERY CO.,LTD , https://www.yiyou-staple.com