SDDN636 Dumas Nitrogen Analyzer

The SDDN636 Dumas Nitrogen Analyzer is a fully automated instrument designed for the rapid and accurate determination of total nitrogen and protein content based on the classical Dumas combustion method.

Both solid and liquid samples can be introduced directly into the analyzer without complicated sample pretreatment. Once samples are loaded, the instrument automatically completes the entire analytical process, including combustion, gas treatment, nitrogen detection and result calculation.

With an analysis time of only 3–4 minutes per sample and an expandable capacity of up to 144 samples, the SDDN636 provides an efficient solution for laboratories handling routine testing or high-throughput analysis.

The analyzer is suitable for a wide range of applications, including dairy products, cereals, flour, meat products, animal feed, brewing materials, fertilizers, automotive and industrial urea, soil, tobacco and plant tissues.

Key Features

High-Throughput Automated Analysis

The analyzer is supplied with a standard 36-position sample tray and can be expanded to accommodate 72, 108 or 144 samples.

Continuous sample loading and unattended operation significantly increase laboratory productivity, making the instrument suitable for both routine testing and large-scale sample analysis.

Fast Results in 3–4 Minutes

A complete nitrogen or protein determination takes only 3–4 minutes per sample.

Compared with traditional wet-chemical nitrogen determination methods, the Dumas combustion method substantially reduces analysis time and simplifies laboratory workflow.

Direct Analysis of Solid and Liquid Samples

The SDDN636 supports the direct introduction of both solid and liquid samples.

The maximum sample capacity reaches:

  • Solid samples: up to 1.5 g
  • Liquid samples: up to 1 mL

The large sample capacity improves sample representativeness, particularly for heterogeneous materials such as food, feed, fertilizer and soil.

Wide Nitrogen Measurement Range

The analyzer provides a nitrogen measurement range of:

  • 0.01–200 mg N
  • 0.01%–100% N

This wide analytical range enables the instrument to handle samples with both low and high nitrogen concentrations.

Excellent Precision and Repeatability

The SDDN636 achieves a relative standard deviation of:

RSD ≤0.5% at 10 mg N

The combination of high-temperature combustion and precise gas-flow control delivers stable and repeatable analytical results.

High-Temperature Complete Combustion

The combustion furnace operates at temperatures of up to 1200°C, enabling effective decomposition and complete combustion of a wide variety of organic and inorganic samples.

The optimized combustion system helps ensure reliable conversion of sample nitrogen into measurable nitrogen gas.

Intelligent Self-Diagnostics

The analyzer automatically performs system monitoring and diagnostic functions, including:

  • Gas-tightness checking
  • Fault alarms
  • Hardware protection
  • Operating-status monitoring

These functions reduce operator workload and help maintain stable instrument performance.

Fully Automated Operation

After samples are loaded, the complete analytical process is performed automatically.

Automated sample introduction, combustion, gas processing, detection and result calculation minimize manual intervention and reduce the possibility of operator-related errors.

Space-Saving Floor-Standing Design

The vertical floor-standing structure eliminates the need for laboratory bench space.

High-quality castors and positioning devices allow the instrument to be moved easily and securely fixed in place when required.

Broad Application Coverage

The SDDN636 is suitable for the rapid determination of total nitrogen and protein in:

  • Milk and dairy products
  • Cereals, flour and milled grain products
  • Oilseeds and animal feed
  • Meat, meat products and pet food
  • Beer, wort and brewing grains
  • Organic, inorganic and biological fertilizers
  • Automotive and industrial urea
  • Soil and environmental samples
  • Tobacco and plant tissues
Applicable International Standards and Methods
Standard No.Standard TitleApplicable SamplesAnalyte
ISO 14891 / IDF 185Milk and Milk Products — Determination of Nitrogen Content — Routine Method Using Combustion According to the Dumas PrincipleMilk and dairy productsTotal nitrogen, protein
ISO 16634-1Food Products — Determination of the Total Nitrogen Content by Combustion According to the Dumas Principle and Calculation of the Crude Protein Content — Part 1: Oilseeds and Animal Feeding StuffsOilseeds and animal feeding stuffsTotal nitrogen, crude protein
ISO 16634-2Food Products — Determination of the Total Nitrogen Content by Combustion According to the Dumas Principle and Calculation of the Crude Protein Content — Part 2: Cereals, Pulses and Milled Cereal ProductsCereals, pulses and milled cereal productsTotal nitrogen, crude protein
ISO 13878Soil Quality — Determination of Total Nitrogen Content by Dry Combustion (Elemental Analysis)SoilTotal nitrogen
AOAC 993.13Nitrogen (Total) in Fertilizers: Combustion MethodFertilizersTotal nitrogen
AOAC 46-30Crude Protein — Combustion MethodCereals and cereal productsCrude protein
AOAC 990.03Protein (Crude) in Animal Feed: Combustion MethodAnimal feedCrude protein
AOAC 992.15Crude Protein in Meat and Meat Products: Including Pet Foods Combustion MethodMeat, meat products and pet foodsCrude protein
AOAC 992.23Crude Protein in Cereal Grains and Oilseeds: Generic Combustion MethodCereal grains and oilseedsCrude protein
AOAC 997.09Nitrogen in Beer, Wort, and Brewing Grains Protein (Total) by Calculation: Combustion MethodBeer, wort and brewing grainsNitrogen, total protein
Specifications

Measurement Range: 0.01–200 mg N or 0.01%–100% N

Analysis Time: 3–4 minutes per sample

Sample Capacity: 36, 72, 108 or 144 positions; continuous sample loading supported

Sample Size: Solid samples: generally ≤1.5 g; liquid samples: ≤1 mL, depending on sample density

Gas Requirements:

  • Combustion gas: Oxygen, purity ≥99.999%, pressure ≥1 MPa;
  • Actuation gas: Nitrogen, purity ≥99.5%, pressure ≥1 MPa;
  • Carrier gas: Helium, purity ≥99.999%, pressure ≥1 MPa

Relative Standard Deviation: RSD≤0.5% (10mgN)

Power Supply: 220 V ±10%, 50/60 Hz

Maximum Power Consumption: ≤4.5 kW

Combustion Furnace Temperature: Up to 1200°C

Dimensions (L × W × H): 710 × 660 × 1085 mm

Weight: Approx. 160 kg

Schematic Diagram
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Customer Testimonials
We have provided a complete set of Sundy testing solutions, including bomb calorimeter, sulfur analyzer, and thermogravimetric analyzer, to the fuel analysis laboratory of Kavçim Cement, a leading integrated cement plant on Turkey’s Black Sea coast. Sundy’s standardized instrument performance bring outstanding practical value to end users. The upgraded solution significantly simplifies daily operations, lowers manual intervention and maintenance costs, and unifies data consistency for routine fuel analysis. We are very satisfied with Sundy’s product quality and technical support, and will continue to promote and recommend Sundy analytical instruments for more industrial laboratory projects in Turkey.
Dr. Karahan, POTANTEK
After more than 10 years of continuous cooperation and market verification, we confirm that Sundy’s products, especially its automatic calorimeters and elemental analyzers, have high precise temperature control, accurate testing results, and ultra-low failure rate. All products are fully compliant with international ISO and ASTM standard, completely meeting the testing demands of coal laboratories, power plants, industrial enterprises, universities and scientific research institutions. We highly recognize Hunan Sundy Science and Technology’s strong production capacity, standardized quality management system, professional technical support team and excellent business credibility. In all our cooperation cases, Sundy has always demonstrated professionalism, reliability and a customer-oriented service attitude.
Dr. Kim, YEONJIN
FAQs

A Dumas nitrogen analyzer is an analytical instrument based on the Dumas combustion method. It determines the total nitrogen or crude protein content of a sample by converting the nitrogen present in the sample into nitrogen gas through high-temperature combustion, followed by quantitative detection.

The method was introduced by the French chemist Jean-Baptiste André Dumas in 1831.

The analytical process consists of four main stages:

  1. High-temperature combustion: The sample is completely combusted in a pure oxygen atmosphere at approximately 900–1200°C. Organic and inorganic nitrogen compounds are oxidized, producing a gas mixture containing nitrogen oxides, carbon dioxide and water vapor.
  2. Reduction: The combustion gases pass through a high-temperature reduction tube, where nitrogen oxides are converted into nitrogen gas (N₂).
  3. Gas purification: The gas mixture passes through adsorption columns that selectively remove interfering gases such as CO₂ and H₂O.
  4. Thermal conductivity detection: The purified nitrogen gas is carried into a thermal conductivity detector (TCD), where the nitrogen content is accurately determined based on differences in gas thermal conductivity.

A Dumas nitrogen analyzer can measure all forms of nitrogen present in a sample, including nitrate nitrogen, ammoniacal nitrogen and organic nitrogen.

This is an important difference from the Kjeldahl method, which does not effectively recover nitrogen from nitrates and nitrites.

Compared with the Kjeldahl method, the Dumas nitrogen analyzer delivers much faster analysis, typically completing one sample in 3–5 minutes rather than several hours. It does not require corrosive chemicals such as concentrated sulfuric acid or strong alkalis, making the process safer and eliminating hazardous chemical wastewater. The system is fully automated and suitable for unattended operation, while the Kjeldahl method involves considerably more manual work. In addition, the Dumas method measures all forms of nitrogen, including nitrate nitrogen, whereas the Kjeldahl method does not effectively recover nitrate nitrogen.
A Dumas nitrogen analyzer provides high analytical accuracy. The nitrogen detection limit can reach 0.003 mg, with a recovery rate of at least 99.5% and repeatability, expressed as relative standard deviation, better than 0.5%.

A Dumas nitrogen analyzer can analyze a wide variety of solid, semi-solid and liquid samples. Typical applications include:

Fertilizers: Determination of total nitrogen in compound fertilizers, organic fertilizers and water-soluble fertilizers.

Food: Determination of protein content in dairy products, meat products, cereals and pulses.

Animal feed: Determination of crude protein in animal feed and pet food.

Agriculture: Analysis of total nitrogen in soil and nitrogen content in plant tissues.

Environmental testing: Determination of nitrogen in sludge, water and other environmental samples.

Scientific research: Nitrogen and protein analysis in universities, research institutes and quality inspection laboratories.

No. The analyzer is designed for fully automated operation.

The operator only needs to weigh the sample and place it in the automatic sampler. Combustion, gas purification, detection and data processing are then completed automatically by the instrument.

A single sample typically requires only 3–5 minutes for analysis.

Routine maintenance mainly includes the following:

  1. Before each test: Check the supply pressure of oxygen and carrier gas, and confirm that all gas connections are leak-free.
  2. Regular cleaning: Clean the ash crucible or ash collector according to the sample type, typically after approximately 400 analyses.
  3. Gas-line inspection: Perform a gas-line leak test every two months.
  4. Critical components: Clean the combustion tube and reduction tube weekly to prevent sample residues from affecting the analytical results.
  5. Seal inspection: After maintenance, check that all O-rings and seals are intact and properly installed.

A Dumas nitrogen analyzer typically uses high-purity helium with a purity of 99.999% as the carrier gas and high-purity oxygen with a purity of 99.999% as the combustion gas.

Some instruments may also use argon as the carrier gas.

Compressed air or nitrogen with a purity of approximately 99.6% may also be required for pneumatic actuation.

A Dumas nitrogen analyzer is more suitable for continuous, high-throughput sample analysis.

Because the instrument requires a certain amount of startup time, it is generally recommended for laboratories with a regular or continuous testing workload.

Modern analyzers are often equipped with standby and wake-up functions. The instrument maintains a stable temperature while in standby mode and can quickly return to operating conditions when reactivated, reducing the efficiency losses associated with frequent shutdowns and startups.

Compared with the basic equipment required for Kjeldahl nitrogen determination, the initial purchase cost of a Dumas nitrogen analyzer is relatively high. However, the following factors should also be considered:

Lower labor costs: Fully automated operation eliminates the need for continuous operator supervision.

Lower reagent costs: Large quantities of chemical reagents are not required.

Higher analytical efficiency: Analysis takes approximately 3–4 minutes per sample instead of several hours.

Environmental benefits: No hazardous chemical wastewater needs to be treated or disposed of.

For laboratories processing large numbers of samples, the high throughput and automation of a Dumas nitrogen analyzer can significantly reduce long-term operating costs.

The SDDN636 is supplied with a standard 36-position sample tray and can be configured with 72, 108 or up to 144 sample positions. It supports continuous sample loading and automated analysis, making it suitable for laboratories with different throughput requirements.

The SDDN636 is suitable for nitrogen and protein determination according to widely used Dumas combustion methods, including ISO 14891 / IDF 185, ISO 16634-1, ISO 16634-2, ISO 13878, AACC Method 46-30 and several AOAC Official Methods. These methods cover dairy products, cereals, oilseeds, animal feed, meat products, fertilizers, soil and brewing materials.
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