what is the difference between primary & secondary standards
Primary reference standards are obtained from EP, USP, BP, JP, FP and they are quite expensive.
Secondary reference standards are substances which are prepared by comparison with a primary reference substance. They can be provided from manufacturers and they are also named as working standards.
thanx, is there any proper definition of primary standards
You can find in EP 5.12 reference standards
A standard shown to have suitable properties for the intended use; the
demonstration of suitability being made without comparison to an existing standard.
A standard established by comparison with a primary standard.
Primary standards are also called as reference standards.
Standards of very high purity. They are procured very less
in quantity and hence would be used up for the
standardization and preparation of in-house working standards
which are called as secondary standard. From primary
standard a secondary standard can be prepared in adequate