If the drift during pretitration (conditioning) is too high after the addition of fresh working medium, then this is a sign that the titration cell is not protected sufficiently against humidity. Replace the molecular sieve and the septum, also check whether all of the O-rings/PTFE sleeves are in proper working condition (damage, cracking).
If the drift is too high after the completion of a sample titration, then this is usually because of other reasons:
- The sample has not dissolved completely during titration and continues to release water. An increase of the extraction time or other sample pretreatment steps are recommended. Read for more details in the following FAQ: «What to do to improve the release of water?»
- The sample reacts with the KF reagent, a side reaction takes place. Depending on the type of the side reaction, this can be suppressed not only with special reagents, but also by means of appropriate titration methods (KF oven method, titration in the cold, or external extraction).
- The sample has shifted the pH value. Read for more details in the following FAQ: «How can I prevent side reactions or pH value shifts?»