BUCHI KjelSampler K-377 - Manual (Page 144)

8 Troubleshooting
144 K-375/376/377 Operation Manual, Version B
Boiling retardation/bumping/foaming
• Missing digestion rods or boiling stones are used
• Missing Antifoam tablet or other anti-foaming agent
Typical mistakes distillation
Samples do not get dark blue/brown after addition of NaOH
• Empty NaOH tank
• Air in NaOH hose
• No catalyst used for digestion (only H
2
O
2
)
Splashing during distillation or addition of chemicals
• Choosen wrong sample tubes
• Volume in sample tubes too high
• Not enough water used for dilution
Other problems that may occur
Problem Cause Corrective measure
Nitrogen content too high • Air in titration system, buret, tubes
• Carry over during distillation
• Wrong titrant
• Error in calculation
• Defective pH electrode
• Dirty glassware
Refill buret
Use less volume, or increase water
volume for dilution
Use right concentration
Check calculation and concentration
of titration, molar reaction factor,
factor of titrant
Calibrate electrode, replace if neces-
sary
Only use clean glassware