Home / Protein (Dumas) Test

Protein (Dumas) Test

  • 29 per analysis
  • |
  • 7 - 9 Business Days
  • |
  • Rush Available
Our commitment to quality

You can expect high-quality, reliable results time after time.

Learn More
Protein (Dumas) Test

Technical data sheet


Method description

The sample is completely combusted at high temperatures in the presence of pure O2 (99.9%). Combustion products are H2O, CO2, NOx, and N2. Water vapor, oxygen, and CO2 are removed from the resulting gas stream by a series of thermoelectric coolers and chemical sorbents. NOx is reduced to N2 when passed through a column packed with hot copper. The resulting N2 is passed to a thermal conductivity detector where it is quantified (helium is the carrier gas). Protein is then calculated from the nitrogen content using a published conversion factor (e.g. 5.70 for wheat).

Acceptable matrices

This method is universal for the determination of nitrogen content and can be used for nearly all food products.

Unacceptable matrices

Pure oils and shortenings cause fires in the instrument and must be assayed by the Kjeldahl method.

Limit of quantitation

0.125% Nitrogen
0.648% – 0.798% Protein (factor dependent)


Protein/Nitrogen by combustion analyzer.

Method reference

AOAC 992.15; AACC 46-30

Reportable unit

% Protein

Sample size requirements

20 grams

Additional information

Available protein factors:

  • 6.25 – general-purpose food products/ingredients (default) except as noted below
  • 5.70 – wheat, wheat flour, and wheat flour bread
  • 6.38 – dairy
  • 5.46 – peanuts and brazil nuts
  • 5.18 – almonds
  • 5.30 – other tree nuts (coconuts, butternuts, cashews, chestnuts, hazelnuts, hickory nuts, pistachios, walnuts, and pecans)
*Prices and offerings are subject to change without notice.

Common Protein (Dumas) Test Testing Questions

While our sales and customer service team are happy to answer general testing questions, consultations typically start at a rate of $250 per 30 minutes regarding the interpretation of reported test results or questions about our test methods. We cannot consult on regulations, tolerance limits, or claims.

We make every effort to keep our methods and detection limits up to date according to the latest standards and qualifications. If you have any questions regarding the limit of detection/quantification or method references, please contact our Customer Service team at 1-800-245-5615.

Our standard turnaround time is 10 business days for most assays. There are some assays that require a longer turnaround time. We also offer a RUSH service that is half the time of the standard turnaround time of the assay at double the cost of the assay. A few assays that we provide cannot be rushed due to the nature of the test. Please check the specific assay you are interested in regarding the ability to RUSH the turnaround time.

Medallion Labs, a division of General Mills, offers multiple areas of expertise for analytical testing and product evaluation for the food and ingredient industry. Our areas of expertise include Chemical Analysis, Nutritional Analysis, Food Safety, Shelf Life Studies, Microbiology, Specialty Fibers, Physical Testing, Allergen Testing, as well as Product Evaluation (which includes Product Performance and Sensory Evaluation) and Technical Consulting/Method Development. Our methods are developed for the testing of food products and ingredients.

Do you have a more specific question?

Our food testing experts are here to help.

"*" indicates required fields

This field is for validation purposes and should be left unchanged.
Ask a food testing expert a question

Let’s Get to Work!

Submit your order online and ship your samples today. If you have questions, we are always here to help.

Medallion Labs

A food testing program designed with mid-market and enterprise food and ingredient manufacturers in mind.