ANKOM 2000 Series - Manual (Page 42)

Operator’s Manual
pg. 42
Rev E 1/14/15
Precision
Results of the collaborative study (see Tables 1&2) indicate the
precision (S
r
, RSD
r
, r) that the analyst should use as a benchmark for
evaluating replication in the same laboratory.
Calculations
% Crude Fiber = 100 x (W
3
– (W
1
x C
1
))
W
2
Where: W
1
= Bag tare weight
W
2
= Sample weight
W
3
= Weight of Organic Matter (loss of
weight on ignition of bag and
fiber)
C
1
= Ash corrected blank bag factor
(running average of loss of weight
on ignition of blank bag/original
blank bag)
Numbered Notes
1. F57 filter bags may produce up to 0.5% units lower values on
finely ground samples. Finely ground samples have fiber
particles less than 25 microns.
2. A running average blank bag correction factor (C
1
) should be
used in the calculation of fiber. The inclusion of at least one
blank bag in each run is mainly used as an indicator of particle
loss. A C
1
larger than 1.0000 indicates that sample particles were
lost from filter bags and deposited on the blank bag. Any fiber
particle loss from the filter bags will generate erroneous results.
If particle loss is observed then the grinding method needs to be
evaluated.
Crude Fiber Procedure (continued)
10. Attach each Cubetainer hose to the Cubetainer and to its
specific port. Port A is used for Crude Fiber Acid solution.
Port B is used for Crude Fiber Base solution.
11. Open the Vessel Lid and insert the Bag Suspender with bags
into the Vessel and place the Bag Suspender Weight on top
of the empty 9
th tray to keep the Bag Suspender submerged.
12. Follow the instructions on the ANKOM 2000 display:
a. Select Crude Fiber.
b. Close Vessel Lid.
c. Confirm hot water is on (>50°C).
d. Press START.
13. When the Crude Fiber extraction and rinsing processes are
complete, open the Vessel Lid and remove the samples.
Gently press out excess water from the bags. Place the bags
in a 250ml beaker and add enough acetone to cover the bags
and soak for 3-5 minutes.
CAUTION4: Acetone is extremely flammable. Avoid static
electricity. A fume hood should be used at all times when
using acetone.
14. Remove the filter bags from the acetone and place them on a
wire screen to air-dry. Completely dry in an oven at 102 ±
2°C. (In most ovens the filter bags will be completely dry
within 2-4 hours.) NOTE: Do not place bags in the oven
until the acetone has completely evaporated.
15. Remove the filter bags from the oven and immediately place
them directly into a collapsible desiccant pouch and flatten
to remove any air. Cool to ambient temperature and weigh
the filter bags. NOTE: Do not use a conventional desiccator
container for this step.
16. Ash the entire filter bag/sample in a pre-weighed crucible
for 2 hours at 600 ± 15°C, cool in a conventional desiccator
and weigh to calculate loss of weight of organic matter (W
3
).