Analytical Balance Calibration

[Sunjay]

Dear All,

I just want to know how to set limits for the Corner Load test (Ecentricity Test) and Hysteresis test for the analytical balance calibration.

We have Mettler Toledo balance with readibility 0.01 mg.

If someone is doing and have referances pls share it.

Thanks

[rnelson]

USP has a new draft version of <1251> circulating for comments that explain the limits for both tests. The criteria for both are "errors should not exceed 0.1% of load".

The way it described the hysteresis test seems no different than the linearity test though, so I'm not real sure what the difference is. It described performing hysteresis at 0%, 50%, and 100% - but if I test linearity at those points, again what's the difference?

Hope that provides a little guidance.

[DR]

Not too sure about the tests you mention, but you should get familiar with the USP definition of "accurately weighed" - the part about the error being <3x the stdev. You will find that the balance resolution (0.01g) has little to do with its lower limit for getting USP accuracy (which may well not matter if you are only using it to make mobile phases...).