METHOD FOR DETERMINATION OF NITROGEN IN MEAT SAMPLES
Ref: TN234, Rev. 1
Introduction: The 440 Elemental Analyzer can perform direct automated elemental analysis of total nitrogen with a minimum of sample preparation. Sample Preparation 1. Weigh out 100 - 200 grams of meat sample into an aluminum weighing pan. Record the weight. 2. Place the sample in a drying oven at 90oC for 12 hours. For fresh meat a higher temperature and a shorter drying time may be used. As a guideline try 120oC for 7 hours. 3. Re weigh the sample. The weight difference reflects the dry matter of the sample. Dried weight / original weight x 100 = % dry matter. 4. Grind the dried sample to a 35 mesh size, or a particle size of roughly .5 mm 5. Weigh out 1 - 3 mg of the ground sample into a tin capsule. Calibrate the instrument and run the sample as normal. 6. Multiply the % Nitrogen result as determined by the CE-440 by the % dry matter to reflect the drying procedure. The initial result will be artificially high due to the moisture being driven off. Therefore Result % x Dry Matter % / 100 = Correct Result. For further information on nitrogen analysis, see Tech Brief 221.