Balances and Micropipettes By Paola Restrepo and Ankita

Balances and Micropipettes By: Paola Restrepo and Ankita Desai

Balances n Types Micro balances n Top Loaders n Analytical Balances n Floor Scales n

Validation n Pre-purchase meeting with QA, users, and a member of Metrology n n n Discuss the user requirements and the suitability of the proposed balance to be purchased. The Lab Strategy form is completed once the equipment arrives to determine whether it will be used for GXP purposes. If the unit is to be validated, protocols are drafted, reviewed and approved by the user and the validation team. Example of protocols include the Installation Qualification and Operational Qualification. n Additional task include: n n n The calibration/maintenance requirements to be performed periodically. Users and Metrology will create or revise any SOPs (use/calibration). Once all of the pertinent documents and tasks are executed, reviewed, and approved (meets all specifications), the balance may be release for GXP laboratory purposes.

Calibration n n All of the calibration requirements (determined during the validation phase) are setup in the validated software database referred to as Calibration Manager. The database information n n Includes the location of the equipment, user department, cost of unit, history (calibration, unscheduled repairs, etc. ), scheduling, and calibration data references. Calibration scheduling may include monthly, quarterly, and semiannual checks.

How its done? n n The monthly checks may require minimum and maximum weight checks. The monthly uncertainty is checked using the min weights. Additional maintenance is done as required. The semiannual calibration checks may involve the use of an approved outside vendor to perform calibrations and maintenance n Includes lubing and thorough cleaning.

Accuracy n n Accuracy Checks are done using calibrated Class 1 weights. During Calibration n n Min/Max +/- 0. 1 % (measured vs. certified); Uncertainty +/- 0. 1 % (repeat of 10 measurements of the min) Daily Activities n Min +/- 0. 1 % (measured vs. certified)

Weights n n The weights are calibrated by a certified vendor. Solvay sends their weights to Heusser Neweigh.

Daily Use n n Users perform daily checks using the minimum weight accepted on the balance. This is required before the balance may be used for any GXP purposes that day. The daily accuracy specification is the certified minimum weight vs. the measured minimum weight +/- 0. 1 % of the weight. The daily checks along with any other entries such as the material to be weighed are recorded in the logbook. The logbook is cross referenced with the lab notebook.

Micropipettes n n n Micropipettes are used to transfer small liquid volumes. It is used for more accurate and precise measurements of volumes smaller than 1 ml. It was invented in 1957 by Heinrich Schnitger in Germany.

Micropipettes n n Micropipettes have 3 positions: n Rest position. n First stop. n Second stop. How to use it : n Set volume. n Attach disposable tip. n Depress the plunger to 1 st stop. n Immerse tip in sample and Draw up sample. n Withdraw the tip. n Dispense the sample by pushing the plunger to the 2 nd stop. n Withdraw the pipette and release the plunger. n Discard the tip

Accuracy and precision n n Optimal range: 35% - 100% of volume Use a correct immersion angle. Pipette perpendicular to solution. Withdraw tip slowly and smoothly from liquid. Maintain controlled aspiration rates. Don’t let plunger snap back. Be consistent with pipetting rhythm, pressure on the plunger and speed.

Micro Pipettes n n The pipettes are purchased based on the users preference. Solvay Pharmaceuticals typically purchases from Eppendorf. Standard pipettes are not validated (IQ/OQ) Calibrated on a semiannual basis

Calibration n Solvay’s calibration is currently done by Troemner has been audited and deemed as an acceptable vendor to calibrate them. They do “As Found” (when received or as is) and “As Left” (after adjustments/maintenance).

References: n n n http: //us. mt. com/home http: //en. wikipedia. org/wiki/Micropipette Solvay Pharmaceuticals