Weighing procedure with microbalances
NB! only trained/approved users may use the microbalances, never exceed the maximum weight range for a given balance.
Write yourself on the list/check if the microbalance is available.
Clean the working bench and weighing equipment with Kim Wipes/brush.
Check that the weighing pan is clean. If it is not, clean VERY carefully with a brush, contact Anna Kieu-Diem Tran if unsure how to remove contamination.
Avoid jarring or vibrating the balance. Do not place vials, racks or other equipment on the anti-vibration table or on top of the microscale to prevent destabilizing the balance.
Cover open vials on the bench with plastic sheet or clean paper to prevent dust from falling in.
Standards can be found in the standard desiccator.
If the standard is in a bottle with cap: Open the bottle only when you remove standard out of it with a clean small spatula and close it immediately after use. DO NOT PUT MATERIAL BACK INTO THE STANDARD BOTTLE AND NEVER POUR STANDARD OUT
Carefully place an empty weighing boat or weighing paper onto the balance using tweezers (do not touch with your fingers). Be careful to not press down on the weighing pan! Never put samples directly onto the weighing pan.
Tare the balance.
Take the weighing boat out again and place standard/sample material in the middle of the weighing boat/paper.
Place the weighing boat/paper with standard/sample onto the balance again.
Close the draft shield before reading the result.
If the weight is too large: remove the boat from the microscale and pick/pour the extra grains out on a tray/weighing paper. You can reuse the material if the tray/paper is clean.
Read the result only after the small round circle in the upper left of the balance display has disappeared.
Make sure the Kiel vial/exetainer is clean before you carefully lead the boat towards the bottom of the vial in a horizontal position.
Turn the vial and boat in a vertical position before pouring and carefully knocking the boat towards the wall to ensure that all material is located in the vial.
Take the boat out of the vial and weight the boat again to double-check that it is no material left in the boat.
Tap the vial with a tweezer to collect the material at the bottom.
For weighing out a new type of standard use a brush and Kim Wipes to clean the weighing boat and tray or change weighing paper.
Place the standard back in the desiccator as soon as you are finished.
Once you are done, clean after yourself!