Close the Vessel Lid tightening it by turning the Vessel Clamp Handle.
Press START on the Keypad. Solution will flow first into the vessel through Port A.
Once the analysis begins, digestions and rinses occur automatically, with the
analyzer Display providing information about the process time remaining, the
temperature, and the pressure. Pressing STOP on the Keypad at any time
during the analysis ends the operation and opens the drain to exhaust the
solution.
When the “Extraction Done” message appears on the Display, the analyzer operation is complete. Open
the Vessel Lid, remove the bags and place them in an appropriately sized beaker.
With your hands, gently press out excess water from the bags into the
beaker and pour off the water from the beaker.
With the bags in the beaker, add enough acetone to cover them. Let the bags
soak in acetone for 3 – 5 minutes. Then pour off the acetone.
With your hands, gently press out excess acetone from the bags into the
beaker and pour off the acetone from the beaker.
Remove the bags from the beaker and place them on a wire screen to air-dry.
Hazardous Materials – Do NOT place bags in an oven until all acetone has
evaporated.
Place air-dried bags in the oven and heat at 102°C ± 2° for 2 – 4 hours (depending on the oven).
Remove the bags from the oven and place them in a Desiccant Pouch.
Do NOT use conventional countertop or cabinet
desiccators for this analysis.
Allow the bags to cool to room temperature. This should take about 10 – 15 minutes.
Re-weigh each filter bag immediately after removing from the Desiccant Pouch.
Ash all filter bags in pre-weighed crucibles for 2 hours at 600°C ± 15°.
Cool the ashed crucibles in a conventional desiccator.
Weigh the ashed crucibles to calculate the loss of weight of organic matter (W
3
).
Calculate Crude Fiber using the following formula.
Weight of Organic Matter (loss of weight on ignition of bag and fiber)
Ash corrected blank bag factor (running average of loss of weight on
ignition of blank bag / original blank bag)