Karl Fischer Titrator — Standard Operating Procedure

1. Pre-Operation

• [ ] Verify anode/cathode solution levels
• [ ] Check stirrer function
• [ ] Run blank drift check (<5 µg H₂O/min)
• [ ] Verify with water standard (recovery 98–102%)

2. Sample Analysis

1. Tare balance with sample boat
2. Weigh 5 – 50 mg peptide (record exact mass)
3. Transfer boat to titration vessel
4. Close septum
5. Start titration
6. Record water content (µg and %)
7. Rinse vessel between samples

3. Acceptance

Parameter	Criteria
Drift	<5 µg H₂O/min
Standard Recovery	98 – 102%
Bulk Peptide	≤1.0%
Formulated	≤0.5%