Gerhardt Kjeldahl Nitrogen / Protein Equipment

Gerhardt produce a wide range of equipment for the analysis of Nitrogen/protein in foods, feeds, soils, sediments, sludges and other materials. The Kjeldahl method consists of 3 stages; Digestion, distillation and titration.


Gerhardt supply the widest range of options for Kjeldahl digestion on the market. Traditional hotplates, Aluminium hot blocks, Kjeldatherm, and infra-red heaters, Turbotherm.

Traditional heaters, Kjeldatherm and Turbotherm all have different qualities which can be matched to your particular requirements. We are happy to advise on the best digestion equipment to suit your sample type and numbers.

The new Kjeldatherm aluminium digestion blocks feature a new programmable controller for all blocks, bigger display size, easy viewing with additional windows, pre-heat function, optional end of run alarm, pre-defined methods, data logging, optional lift control, backlighting on digestions in lift models. 8 or 20 place blocks are available.

Turbotherm – infra red heating systems feature fast heating and cooling for speed and safety. Programmable and very useful for frothy samples the Turbotherm can be set up for 4 x 800ml, 4x400ml, 6x 200/300ml, 12 x 200/300ml and 12 x 100ml digestion tubes. Acid fumes are either removed by the water jet pump supplied with Kjeldatherm and Turbotherm systems, or the Vacusog fume scrubber system.

Distillation and Titration

The Gerhardt Vapodest range features touch screen control, precision dosing and use low voltage systems wherever possible for safety.

All Vapodests feature a Quick Start Option, pre-programmed method menu along with customised favourite methods, easy clean surfaces and have backlighting to aid display. The distillation area and tube support allows the use of a huge range of tubes and flasks from 100ml to 1.3 litres. Receiver vessels such as Erlenmeyer flasks, beakers, volumetric flasks or bottles can also be accommodated in the generous distillation area.

The structure of the new Vapodest allows easy access for service and maintenance as well as providing structural barriers between distilling, pumping and control functions. The steam generator has been designed for easy cleaning and has considerable insulation for safety and efficiency.

  • Vapodest 200 is programmable for addition of a reagent, such as NaOH, reaction time, distillation time, and steam power.
  • Vapodest 300 has the features as above plus sample dilution and sample waste removal.
  • Vapodest 400 has all the features of the 200 and 300 plus that addition of the receiver solution.
  • Vapodest 450 has all the features above plus the option to link to a titrator for direct titration of the distillate.
  • Vapodest 500 fully automates the distillation and titration process producing and storing results according to ISO9001, 17025 and GLP.
  • VAP 500 Carousel system for fully automated Kjeldahl analysis with automatic sample loading from the ever reliable carousel system.