BÜCHI Labortechnik AG

Model K-350 / K-355 - Laboratory Distillation Unit



Perform Kjeldahl nitrogen or protein determinations compliant to officially approved methods in the most cost effective way. Expand your range of applications with the additional features of the K-355.


  • Entry level instrument for Kjeldahl and other steam distillations
  • Eco-friendly cooling water control reduces water consumption
  • Plastic splash protector for extended lifetime

Ease of use

  • Simple programming of distillation parameters
  • Straightforward operation and calibration of reagent pumps
  • Multiple method recall for routine analysis with the K-355

Wide-range use

  • Acid resistant pump allows additional steam distillation applications
  • Reduction of steam power for gentle steam distillation
  • Choice of plastic or glass splash protector

Safety features

Automatic dosage of chemicals, protective sensors for sample tube, front door and service door ensure safe operation.

Save cooling water

Start and stop cooling water automatically during the distillation process.


Splash protector

Choose between the long-life plastic splash protector or the glass splash protector for visual control of the chemical reaction.

Steam regulation

The K-355 regulates the steam power to control foaming samples and exothermic reactions.

Specific sample tubes

Chose the appropriate sample tube according to the application to match the required sample amount.

Scientific mobile apps

Manage your data with ease for a more efficient daily routine.

  • Kjeldahl Optimizer
  • Kjeldahl Reports

Feed - Kjeldahl

Protein, Non-Protein Nitrogen (NPN)

Environmental Analysis - Distillation

Ammonia, Total Kjeldahl Nitrogen (TKN), phenol, formaldehyde, nitrate, nitrite (Devarda)

Pharmaceutical / Cosmetics - Distillation

Organic nitrogen, ammonia, urea, formaldehyde

Food - KjelFlex

Protein, Non-Protein Nitrogen (NPN), casein (NCN), Total Volatile Basic Nitrogen (TVBN), sulfur dioxide (SO2), formaldehyde

Beverage - KjelFlex

Protein, alcohol, volatile acids, diacetyl, sulfur dioxide (SO2)

Chemicals / Agricultural - KjelFlex

Ammonia, nitrate, nitrite (Devarda), cyanide (CN), total nitrogen

Glass splash protector
With its extensive know-how BUCHI provides state-of-the-art glass parts like the splash protector. The whole distillation process is visible for easy method development and process monitoring.

Plastic splash protector

This splash protector is made of glass fiber reinforced polypropylene. It is the choice for high throughput analysis due to its long lifetime.

K-355 with acid resistant pump

Some direct distillations require the addition of an acid to the sample prior to the distillation process. With theK-355 integrated acid resistant pump adding the acid can be automated.

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