Ankom TDF, Operator'S Manual

Page: 45 / 78

Operator’s Manual
Rev A 4/30/12 pg. 45
SDF / TDF – Kjeldahl Method
To determine the protein content within the SDF or TDF residue, follow the procedure below.
1. Cut the filter bag just above the seal at the top of the filter.
2. Fold the remainder of the filter bag in thirds from side to side.
3. With your Heat Sealer set to “6,” press the arm down for 3 to 4 seconds to seal the polypropylene edge of the
filter bag.
4. Label the folded, sealed filter.
5. Repeat steps 1 – 4 for all SDF bags that will be used for determining protein content.
6. Run a Kjeldahl procedure on each filter bag using 27 ml of H
2
SO
4
, 10 g of K
2
SO
4
, and 30 mg of CuSO
4
.5H
2
O in a
system with 250 ml tubes that have a 42 mm diameter. Pellets can be used if an equivalent amount of K
2
SO
4
is
added. To slow down the rate of foaming during the digestion process, ramp up the temperature slowly.