Titration; Total Acid Number calibration tips for auto titrators
Talking points you can review while listening to the Podcast:
For TAN titration, two calibration steps are recommended.
STEP1: Calibrate pH electrode
STEP2: Factor Calibration
STEP1: With the proper pH buffer solution- run a pH calibration check by pressing key “[Calib.]“(note: for KEM potentiometric titrators). This electrode calibration must be performed before the measurement. It is possible to do this every day or once in per week.
STEP2: Factor Calibration of the reagent concentration.
To do this the operator must have the standard sample,
For TAN titration the reagent is Base solution.
A general factor titration application note “FactorofsodiumHydroxide.pdf” can be downloaded at: http://www.scientificgear.com/Downloads/Application-Notes?range=11%2C20%2C20
Here is a very simple procedure suggested for TAN calibration/instrument check for all AT-Potentiometric automatic titrators using a pH probe such as C373.
1. Use a 0.1 Normal NaOH (sodium hydroxide) as the titrant in the burette.
2. Pipette exactly 5.0 mL of 0.1 Normal HCl (hydrochloric acid) into a clean beaker and dilute with distilled water.
3. Make sure the instrument is set for Endpoint detect.
4. Press run/start on the instrument to start the titration
5. Record the titrant volume from the printer or screen.
Note: The titrant volume should be very close to 5.0 mL since it should take 5.0 mL of NaOH (base) titrant to Neutralize 5.0 mL of HCl (acid) in the beaker. Acceptable result would be 5.0 mL +/- 0.1 mL.
If the result is not within the tolerance of 5.0 mL +/- 0.1 mL, the probe could need replacing.