Test Price:
$27 per analysis
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.
Detection Limit:
0.1% Nitrogen
Quantitation Limit:
0.125% Nitrogen
0.648% – 0.798% Protein (factor dependent)
Sample Size Requirements:
20 grams
Equipment:
Protein/Nitrogen by combustion analyzer.
Reportable Units:
% Protein
Turnaround Time:
7-9 business days
Is rush testing available?
Yes
Method Reference:
AOAC 992.15; AACC 46-30
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).
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)
Contact Us:
If you have questions about our testing services, please contact us at +1 (800) 245-5615.