Kjeldahl or Dumas? The right nitrogen and protein analysis for your lab

Determining nitrogen and protein content is a critical task for laboratories in food, feed, agriculture, environment, chemicals, and pharma—and selecting the right analytical method is key to achieving accuracy, efficiency, and compliance.

With over 40 years of experience, Velp Scientifica offers both of the world’s most recognised techniques:

• The classical Kjeldahl method for its versatility and broad sample compatibility
• The Dumas combustion method for its speed, automation, and safety

But which is right for your application? Below, we explore the benefits and best-use scenarios for both techniques, helping you determine the ideal fit for your lab.

Kjeldahl method: Unmatched versatility for all sample types

The Kjeldahl method remains the global reference standard for total nitrogen and protein determination, with acceptance across AOAC, ISO, and EPA methodologies. It is particularly suitable when method flexibility and compatibility with diverse organic matrices are priorities.

Kjeldahl is especially well-suited to food and feed analysis - including meat, dairy, grains, pet food, fruits, and vegetables - as well as environmental samples such as soil, fertilisers, wastewater, and sludge. It also applies to complex matrices in pharmaceutical and chemical industries, including polymers, textiles, rubber, and plastic, and can be used for beverages with challenging formulations.

This method delivers high precision and repeatability across a wide range of solid, liquid, and semi-solid samples. It ensures full compliance with international standards and supports scalable automation, offering options from semi-automated to fully automated workflows. Titration compatibility (colorimetric or potentiometric) and integration with the Velp Ermes cloud platform on selected models provide further flexibility and convenience.

Kjeldahl is the method of choice when working with varied or complex samples, where official compliance and methodological adaptability are essential—particularly in high-fat or challenging matrices.

Dumas method: Fast, Safe, and ideal for high throughput

The Dumas technique, also known as combustion analysis, offers a primary method for nitrogen determination that delivers results in just a few minutes. It is entirely chemical-free, fully automated, and designed for rapid, high-throughput workflows.

Dumas is best suited for food and feed quality control labs that need fast, consistent results, production environments requiring minimal operator input, and laboratories that analyse standardised, low-fat samples. It’s also ideal for facilities prioritising safety and ease of use.

With sample turnaround times under five minutes, Dumas offers excellent reproducibility and accuracy. The method is safe for operators, eco-friendly, and compliant with major international standards including AOAC, AACC, and ISO. Integration with the Velp Ermes cloud platform further enhances remote monitoring and data management.

This method is ideal if your lab demands speed, high throughput, and minimal supervision—particularly for routine testing on homogeneous samples.

Why choose Velp? Expertise, flexibility, and support

Whether your needs point to Kjeldahl, Dumas, or a combination of both, Velp delivers robust, high-performance instrumentation backed by decades of scientific expertise. Each system is designed for long-term durability and reliability, supported by original consumables that ensure optimal results and operational efficiency.

Velp solutions reflect Italian design and craftsmanship and feature modular configurations that scale with your laboratory’s growth. With cloud connectivity for remote access and tracking, plus expert application guidance and service support, Velp provides a complete ecosystem for nitrogen and protein analysis.

All solutions meet major international compliance standards, giving you peace of mind along with precise data.

Talk to our experts to find the best solution for your lab - whether you prioritise speed, versatility, or regulatory compliance.

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