What is the frequency of determination of minimum weight for analytical weighing balance


(Ravi Velamuri) #1

What is the frequency of determination of minimum weight for analytical weighing balance.
Is it sufficient only during the initial qualification?
Or a periodic determination of minimum weight is required?
If period determination of minimum weight is required, what is the frequency?


(Dr. Ahmed Mohamed Awad) #2

For analytical balances , the minimum weight depends on repeatability test result (Standard Deviation) as illustrated in USP 1251
It is typically done once a year as mentioned in OMCL Annex 8


(Dr. Ahmed Mohamed Awad) #3

When you determine SD of analytical balance during repeatability test , directly the minimum weight can be calculated using minimum weight formula present in USP chapter 1251


(Dr. Ahmed Mohamed Awad) #4

Note that it is recommended to apply a safety factor (2 by default) when determining minimum weight as illustrated in Mettler Toledo GWP.