Thermo Fisher Scientific TN100 Turbidimeter - Manual (Page 11)

Instruction Manual TN-100/ T-100
6
2.3
Calibration Procedure
Preparing the Standard Vials
Each standard vial should be used with the same standard value (0.02, 20.0, 100, or
800 NTU) for the greatest accuracy. Follow the steps below at each change of solution.
1. Ensure there are no scratches or marks on the glass vial. If there are marks that
could affect the turbidity measurement, select another vial.
2. Slowly and gently invert the calibration standard plastic bottle five times but do
not shake the bottle as air bubbles can affect the reading.
3. Rinse a clean vial with 3-4 mLs of the calibration standard that will be used in
this vial. Invert the capped vial 5 times. Uncap and dispose of the rinsate.
4. Repeat the rinsing steps and dispose of the rinsate.
5. Fill the vial with the primary standard solution to the fill line and cap the vial.
6. Clean the exterior of the vial using a lint-free cloth to remove all traces of liquid,
dirt or fingerprints. Remove stubborn smudges with alcohol or a non-abrasive
glass cleaner, and silicone oil can be used to fill small external scratches on the
vial.
7. Repeat Steps 1-6 to prepare the other three standard solutions.
These standard vials can be used to check the meter calibration by reading back
the standard value daily and also be used for calibration when needed. When the
standard reading of 20.0, 100, or 800 NTU drifts more than 10% of the standard’s
NTU value, the solution should be replaced with another aliquot from the plastic
bottle following the Preparing the Standard Vials steps . The 0.02 NTU standard
read back value should be <0.1 NTU.