Skip to main content

FAQ

I am experiencing high or low assay results. What should I do?

Check to ensure the procedures sent with your instrument were followed. Some possible variables that may affect your results are:

General Problems:

  • Neutral Detergent chemicals can come out of solution. Heat and stir to bring back into solution.
  • The temperature controller settings were modified. This can produce improper heating.
  • Oven temperature is too hot (should be at (102°C +/-2°C)
  • Improper weighing technique. Refer to the Operator's Manual sections on sample preparations.
  • Improper or non-use of the MoistureStop Dessicant Weigh Pouch. A standard desiccator will introduce moisture in the samples as it is being opened and closed. This will cause poor precision. The ANKOM MoistureStop Dessicant Pouch (Part #: X45) should be used.  

Low Values:

  • The grind is too fine.
  • The bag is not completely sealed.
  • A broken seam in Filter Bag is allowing sample to escape from bag.
  • The digestion runs too long (ADF & Crude Fiber).

High Values:

  • The movement of the Bag Suspender is less than 1/2" (1.2 cm) up and down. Refer to the Periodic Maintenance section of the Operator's Manual. Follow the steps to check the agitation system.  
  • The solution is not heated sufficiently. Perform the boil test detailed in,
    • For DELTA, the Service Procedure Controller Menu Setup (DES015) or Operator’s Manual.
    • For A200, the Service Procedure Boil Test and Controller Temp Calibration (FS013).
    • For A2000, the Service Procedure Boil Test (AS013).
  • For NDF - Failure to use Alpha Amylase and/or Sodium Sulfite.
  • For ADF/NDF - Failure to pre-treat samples with high-fat content (>5%) with solvent.
  • For Crude Fiber – The sample was not presoaked with petroleum ether. It is always required to pre-soak with petroleum ether for crude fiber runs.
  • Sample is not sufficiently dried. This could be a result of the oven temperature being too low, or wet samples introduced next to dry samples.
  • Lack of or incorrect use of the MoistureStop Weigh Pouch. Check for holes in the pouch. The MoistureStop Weigh Pouch should be dried regularly to refresh the desiccant. Follow the directions on the label.  
  • Rinse water not hot enough or not long enough. Water should be 70°C for NDF and ADF and 50°C for CF. The rinse should run for 5 minutes.
  • Digestion is not run long enough.
  • Acetone was re-used for removing water from bags post extraction.
  • Improper calculation of blank bag correction or using the wrong values in the formula.
  • The Filter Bag was sealed too low.
  • Too much sample in the bag.
  • The sample was not spread out in the bag.
  • The vessel lid was not closed tightly enough.