S.O.P. for Balance Operation and Cleaning

Prepared by: Joshua Alfaro

Last update: 04-06-09

File: TMPT C:\Josh1\SOP\Balance_SOP

Balance Operation:

  1. Talk to Josh to receive a brief tutorial on balance operation.
  2. Make note of the balance’s maximum (total weighing capacity) and minimum weighing limits and the error of the particular balance that you wish to use.
  3. Error: do not use the analytical balance unless necessary. Know how precise your measurement needs to be.
  4. While weighing samples use weighing boats or weighing paper to avoid contaminating the balance pan (if area is contaminated clean immediately, .i.e. brush away solids or wash weighing pan with ethanol to remove organic oils or liquids). Also, do not weigh hot or wet containers.
  5. While taring and weighing make sure all balance sliding doors are closed.
  6. Once measurements have been made turn the balance off, remove all reagent bottles from the balance area, dispose of all trash generated during the weighing process (i.e. weighing paper and boats) and clean the area surrounding the balance (even if there are no obvious spills or residue left).
  7. Caution: The balance is sensitive to and maybe damaged by shock. Do not drop heavy objects near the balances.

Problems with the Instrument:

If you believe the balance readings are erroneous check to make sure the balance has been leveled. Then check to see if a known volume of water (use volumetric device) has the appropriate mass when weighed. If problems persist talk to Sunny or Josh.

Cleaning:

  1. Use the brush to gently brush away solids from the weighing pan and the surrounding weighing platform.
  2. Turn of the balance and carefully remove the pan and wash it initially with distilled water then with ethanol. During the ethanol wash avoid ethanol contact with the rubber piece of the weighing pan.
  3. Dry the weighing pan and place it in its former position on the balance.
  4. Clean the balance’s window panes with water and ethanol and dust the remaining areas with Kim wipes.
  5. When weighing measurements are finished remove all reagent bottles from the balance area and dispose of all trash generated during the weighing process (i.e. weighing paper and boats).
  6. The balances and surrounding area will be maintained on a weekly by whoever is in charge of lab clean up duty.