Buchi KjelSampler K-377 Manual de usuario descargar pdf (Pagina 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

2O2)

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

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Buchi KjelSampler K-377 Manual de usuario Pagina 144