Thompson and Capper Kjeltabs are carefully formulated tablets for use in the determination of protein content via the Kjeldahl method.

We have over 20 years experience in the production of Kjeltabs, and we are relied on by the largest suppliers of digestion equipment in the world. We have customers on every continent, and we are truly world famous for our quality and expertise.

The Kjeldahl method is the internationally recognized standard for nitrogen analysis, and it has been for over 100 years.  The technique was developed by a man called Johan Kjeldahl whilst working for the Carlsberg brewery. On March 7, 1883, he presented his method to the Danish Chemical Society, and ever since his work has been studied, extended and perfected. His method is needed more than ever in today’s society. In fact it has become the worldwide standard for protein determination in laboratories all over the world. It is a fundamental tool for the analysis of food products such as meat, dairy produce, cereals and even beer. Furthermore, his method has been modified to determine environmental nitrogen in the form of nitrates and ammonium compounds.

There are three separate steps to the Kjeldahl method, namely digestion, distillation, and titration.  In essence, the digestion stage converts proteins into ammonium compounds, from which ammonia is released upon alkali addition. This ammonia is subsequently collected by distillation. It is then titrated, and quantitatively related back to the amount of protein in the starting material.

There are many types of nitrogen analysis, and also different digester systems. Each might need a different tablet. We aim to cover all applications, and so we manufacture tablets with different chemical compositions and in different sizes.

There are several factors to consider when choosing a catalyst, including the composition of the sample and environmental/safety aspects. Historically Mercury was widely used due to its exceptional efficiency. Today it is rarely used because of its adverse safety and environmental profile. Safer catalysts are preferred today, and we even manufacture ‘catalyst free’ Kjeltabs. It is a matter of balance. For example, selenium catalysts give a very fast reaction time, making them useful for hard to digest fat-containing or heterocyclic compounds. However, catalysts such as copper or titanium might offer a better safety profile.

6) How do I choose the correct Kjeltab?

Please refer to our product selector and product information tables, which provide all the information needed to make the correct decision.

7) What if I don’t see the Kjeltab I need?

Please just give us a call; we simply have too many Kjeltabs to advertise. Over the years, we have developed lots of special grades for unique applications. If we truly don’t have what you need, then we would be very happy to develop a new tablet with you!