Kjeldahl Analyzers

VELP DKL-20 Automatic Kjeldahl Digestion Units

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VELP KS 1000 Scrubber for Kjeldahl

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VELP UDK 149 Automated distillation unit for Kjeldahl

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VELP UDK 159 distillation and titration unit for Kjeldahl

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VELP UDK 169 Fully automatic distillation and titration unit for Kjeldahl

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Kjeldahl Analyzers: Precise Determination of Nitrogen and Protein

The Kjeldahl Analyzers category brings together equipment and systems designed for applying the Kjeldahl method – the most common classical method for the quantitative determination of nitrogen and protein in a wide variety of samples. These systems enable the accurate and reliable execution of the method’s steps, from sample digestion to distillation and titration, and are essential for laboratories in the fields of food, agriculture, environmental analysis, and more.

The Kjeldahl Method: Digestion, Distillation, and Titration

The Kjeldahl method involves three main stages:

1. Digestion: The sample is heated at a high temperature (around 400°C) in the presence of concentrated sulfuric acid and a catalyst. During this process, the organic nitrogen in the sample is converted to ammonium sulfate ((NH₄)₂SO₄). This step requires dedicated digestion units, often with precise temperature control, as well as systems for removing and neutralizing the hazardous acidic fumes produced (Scrubbers).
2. Distillation: After cooling, an excess of strong base (usually sodium hydroxide, NaOH) is added to the digested sample. The addition of the base liberates ammonia (NH₃) gas, which is steam-distilled and collected in an acidic solution of known concentration (typically boric acid). This step is performed using dedicated distillation units.
3. Titration: The amount of ammonia collected in the acidic solution is determined by titration with a standard acid solution (such as hydrochloric or sulfuric acid). From the titration endpoint, the amount of nitrogen in the original sample can be calculated, and from that, the protein content (using an appropriate conversion factor).

Modern Kjeldahl systems allow for full or partial automation of these steps, thereby improving the accuracy, safety, and efficiency of the process.

Key Applications of the Kjeldahl Method

The Kjeldahl method is a reference method and holds crucial importance in many fields:

• Food and Feed Industry: Determination of crude protein content for nutritional labeling, quality control of raw materials and products (dairy, meat, cereals, legumes, etc.), compliance with standards and regulations.
• Agriculture: Analysis of nitrogen content in soils, fertilizers, and plant nutrients, determination of agricultural product quality.
• Environmental Monitoring: Measurement of Total Kjeldahl Nitrogen (TKN) in water and wastewater as part of pollution monitoring.
• Chemical and Pharmaceutical Industries: Quality control and compositional analysis of certain organic materials.

Advanced Kjeldahl Systems from VELP Scientifica and Labotal

Labotal is proud to offer a wide range of systems and components for the Kjeldahl method from VELP Scientifica, Italy – a leading and innovative company in the development and manufacturing of analytical instruments for laboratories. VELP’s solutions cover all stages of the process, from advanced Digesters with precise temperature control and pre-set programs, through efficient systems for neutralizing acid fumes (Scrubbers, such as the KS 1000), to the automated distillation and titration systems of the UDK series. The UDK series includes models with varying levels of automation: from distillation only (UDK 149), through distillation with an integrated colorimetric titrator (UDK 159), up to a fully automated system including an autosampler for 24 samples (UDK 169).

VELP systems excel in high accuracy and reliability, maximum user safety (thanks to automation and efficient fume neutralization), time and reagent savings, and compliance with recognized international standards (such as AOAC, ISO, EPA). Choosing VELP solutions through Labotal ensures you receive not only high-quality, innovative equipment but also professional guidance, application support, training, and maintenance and calibration services from our skilled team of technicians.

Whether you need a complete Kjeldahl system or individual components to upgrade your existing setup, Labotal’s expert team is ready to assist you. We invite you to review the details of the various systems presented in this category. For professional advice, personalized solution configuration, and a price quote, please contact our analytical instrument specialists.