3. Calculate the min sample weight by using the following formula:

       [Standard deviation x 3] x 1000 = minimum sample weight

The in house calibration technician would perform the about test and the minimum sample weight that is calculated would be enter into the Sartorius Genius Balance via the keypad.  If someone attempted to weigh something below the "minimum sample weight" that was calculated the Sartorius Genius Balance would warn the operator by being prompted via the display.

The above example for calculating the minimum sample weight is for reference and should not be considered the present requirement for pharmaceutical guidelines.  Please review the current specifications called out with the United States Pharmacopeia (USP) before performing any weighing in a production applications.

Calibration technicians required to comply USP specifications should obtain a copy of the current USP 28 NF-23 and read the sections regarding the use of balances in full.  Regulations can change and this web page should not be consider the current guidelines.  You can review an example of a calibration procedure that includes SQmin here.

To assist our customers in determining the minimum sample quantity for their balances, Sartorius has incorporated this calculation on the Genius Series and some of the CP and LA Series of balances.  This new feature, called SQmin, will soon be available on many Sartorius semi-micro, micro and ultra-micro balances. For more information, contact Sean Carey ext. 8807 or Rich Stressler ext. 8330 at Sartorius Corporation (1-631-254-4249).

The USP<41> test and the activation of the SQmin program on Sartorius balances is performed by Authorized Sartorius Service Personnel as follows:

• NIST traceable weights of the appropriate weight and class are used to perform the replicate weightings (at least 10x)
• All weight traceability data and data from the replicate weighings are entered onto a USP<41> Test Certificate
• Calculations are performed in strict accordance to USP<41>
• SQmin is activated by an Authorized Service person through the Service Menu
• The experimentally determined value for Sqmin is entered into the balance
• A signed test certificate for testing according to USP<41> is provided by the Authorized Service person to accompany the balance calibration and maintenance documents.

Please note setting SQmin can not be done by end users.  Setting the SQmin is achieve using propriety software connect through the RS-232 interface of the balance.  At this time Sartorius will NOT release this software to the end user enabling the end user to set the SQMin feature.