FP628 Nitrogen/Protein in Organic Samples


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Maintenance-free autoloader

Simple, gravity-fed autoloader allows for unattended analysis up to 120 samples

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By incorporating state-of-the-art hardware and software technology with key improvements in overall instrument performance and reliability the FP628 is the modern nitrogen/protein analyser of solid or liquid organic samples.

Employing recognized Dumas combustion technique, the FP628  is fast, clean and cost-effective alternative to tedious and not-safe Kjeldahl nitrogen digestion methods . Unique combustion gas handling and aliquot dosing system significantly extends the lifetime of the reagents used, lowering cost-per-analysis and instrument downtime, while eliminating the need for chromatographic separation techniques and other costly whole gas analyses. The FP628 complies to approved test methods AOAC 992.23, AOAC 992.15, AACC 46-30, AOAC 968.06, AOAC 993.13, DIN/ISO 13878 for protein determination in Foods, Feeds, Forages, Fertilizers, grain and cereal products.

Benefits :

  • Proven LECO combustion technology, allows system to analyze a wide variety of organic samples with high precision and accuracy under one method and calibration
  • Ability to handle macro sample mass to 750mg of solids and up to 1ml of liquids
  • Maximize Throughput up to 14 analysis per hour while keeping Cost-Per-Analysis Low
  • Complies with AOAC, ASTM, ISO, AACC, and ASBC approved methods
  • Available automation for high workload laboratories


A sample is weighed into a foil or capsule and loaded into autoloader. Simple, gravity-fed autoloader allows for unattended analysis, while increasing long-term reliability of loader. Passing first the purge chamber that is removing atmospheric gas, the sample is introduced to furnace. Combustion gases are swept from the furnace and passing by the thermo-electric cooler collected into aliquot collection system. Use of thermoelectric coolers in LECO analyzers allows efficient moisture removal without the use of chemicals. Aliquot gas is swept through a reduction reagent tube then passes through Lecosorb and anhydrone reagent tube and reaches a thermal conductivity cell for nitrogen detection. Windows -based operating software manages all of the quantitative calculations and saves all of the data for future use on local storage or export it to LIMS. The final result can be displayed as a weight percentage of nitrogen or protein content as defined by the operator.


  • Vertical quartz furnace tube with a maximum temperature of 1050°C
  • Quartz lance directs oxygen flow directly onto the sample, accelerating the combustion process and providing superior recovery
  • Sample mass  50mg up to ~750mg
  • Ballast and aliquot system decreases consumable usage and less downtime for reagent replacement
  • Reticulated crucible collects ash from sample and tin cap or foil
  • LECO proprietary, very robust ceramic combustion tube with longevity of several thousand analyses or more


LECO’s versatile instrumentation can be used to perform a wide range of applications. Please find below a selection of application notes for the most popular applications. Contact our sales and application specialists for more details.

Nitrogen determination in Fertilizer

Nitrogen determination in liquid and solid fertilizers, like Ammonium Nitrate, Urea or others.Learn more...

Determination of Nitrogen/Protein in Whey Products on FP628

Whey protein is a common ingredient in many dietary supplements due to its availability, solubility, and unique functional characteristics. The accurate and precise determination of protein in whey products not only plays a role in the characterization of nutritional or dietary value in dairy products, but may also be a key in determining the quality or category of the whey product. Protein in whey and other food products is most commonly calculated using the measured nitrogen in the sample and a protein factor multiplier (protein factors vary according to the sample matrix).Learn more...

Analysis of Food and Feed

Nitrogen/Protein in Grains, Feeds, and Pet Food by direct combustion by LECO FP628. Ref: 203-821-485Learn more...

Nitrogen/Protein in Flour

Total protein content in Corn Flour, Wheat Flour and Soy Flour by LECO FP628. Ref: 203-821-470Learn more...

Soil and Plant Tissue

Nitrogen in Soil and Plant TissueLearn more...

Options & models


Various options are available for this product. Contact our sales and application specialists to select the right configuration for your application.
Autoloader Maintenance-free autoloader with optional capacity for up to 120 samples
Liquid Autosampler Dedicated liquid auto sampler controlled by the software. Available for nitrogen and carbon/nitrogen configurations
SmartLine diagnostic LECO's convenient internet-based Remote Diagnostics system


Each instrument can be configured to meet your individual lab needs. Contact our sales and application specialists to select the right configuration for your application.
FP628C Nitrogen / Protein Determinator with loader, PC and LECO application software