Chromatography Forum

Hello to all,

I would like to ask if it is possible from regulatory perspective to use two standard weighings of 50mg instead of one of 100mg for the calibration of balance with a minimum net weight of 100mg.

Thank you in advance for your answers

Are you proposing to put two 50 mg weights on the balance at the same time, or to weigh one 50 mg weight twice ?

I don't see any problem with the first, but the second would be pointless; the balance would read zero twice.

Peter

Are you proposing to put two 50 mg weights on the balance at the same time, or to weigh one 50 mg weight twice ?

I don't see any problem with the first, but the second would be pointless; the balance would read zero twice.

Peter

Agreed to point 1, but for point two most likely the balance would not read zero but 50 mg, which is out of the specified range. From a practical point of view this might be OK, but from a regultatory point of view: Don't!

Jörg

Are you proposing to put two 50 mg weights on the balance at the same time, or to weigh one 50 mg weight twice ?

I don't see any problem with the first, but the second would be pointless; the balance would read zero twice.

Peter

Agreed to point 1, but for point two most likely the balance would not read zero but 50 mg, which is out of the specified range. From a practical point of view this might be OK, but from a regultatory point of view: Don't!

Jörg

50 mg is below the 100 mg minimum weight for the balance - therefore it would show a weight of zero. Assuming of course that it is tared to zero before the weight is added.

100 mg is a very high minimum weight for a laboratory balance, and it is presumably being used to weigh weights is a few hundred grams or more. Calibrating at 100 mg is strange under those circumstances.

Peter

50 mg is below the 100 mg minimum weight for the balance - therefore it would show a weight of zero.

Depends if this is physical minimum weight or regulated minimum weight. Our balance in the lab really does display 0.1 mg, but the minimum weight defined by our SOP (whyever) is 20 mg. Sorry for being nitpicking, but the OP asked about regulatory perspective

Jörg

Re-reading the original post, Dimi actually refers to "minimum net weight", which is not something I am familiar with. Maybe it means readability, in which case 100 mg is too small a weight for the low end calibration.

I think that we can agree that, no matter what Dimi actually means, or what the minimum weight or readability of the balance is, two weighings of 50 mg would not be useful for anything.

Peter