DELTA

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

General Problems:

• ND chemicals can come out of solution. Heat (102 - 105°C +/- 2°C ) and stir to bring back into solution.
• Someone modified the settings on temperature controller. This can produce improper heating.
• Improper weighing technique-See weighing technique in the Appendix of the manual.
• Improper or non-use of the desiccant pouch. A standard desiccator will introduce moisture in the samples as it is being opened and closed. This will cause poor precision.

Low values:

• Grind is too fine
• Bag is not completely sealed
• Broken seam in bag allowing sample to escape from bag
• Digestion run 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 your DELTA Operator's Manual section titled Periodic Maintenance.
• Solution is not heated sufficiently-Perform ANKOM Boil Test (see A2000 Service Procedure 13)
• ND- Failure to use Alpha Amylase and/or Sodium Sulfite
• AD/ND-Sample too high (>5%) in fat and not pre-treated with solvent
• Crude Fiber-always presoak with petroleum ether, not acetone
• Oven temp low, wet samples introduced next to dry samples-samples are not sufficiently dried.
• Lack of or incorrect use of desiccant pouch-check for holes in pouch, packets not dried regularly-refresh desiccant
• Rinse water not hot enough (70°C ND, AD) (50°C CF) or not long enough (5 minutes)
• Digestion not run long enough
• Acetone re-used for removing water from bags post extraction
• Improper calculation of blank bag correction or using the wrong values in the formula
• Bag sealed too low
• Too much sample in the bag
• Sample not spread out in the bag
• Vessel lid was not closed tightly enough

Our grinding recommendation for samples to be extracted in our Fiber Analyzer is:

1 mm with a Wiley Mill
2 mm with a Cyclone Mill (such as UDY or Retsch)

F57

The porosity of the ANKOM F57 Filter Bag is 25 microns. The design of the filter bag provides a 3 dimensional filter matrix similar to the filtering effect of a glass crucible. The F57 Filter Bag provides equal filtration without the manual intervention required with a crucible method.

F58

The porosity of the ANKOM F58 Filter Bag is 6-9 microns. The design of the filter bag provides a 3 dimensional filter matrix similar to the filtering effect of a glass crucible. The F58 Filter Bag provides equal filtration without the manual intervention required with a crucible method.

Depending on what you are testing, refer to section ADF Analysis, NDF Analysis, or Crude Fiber Analysis in the ANKOM^DELTA Fiber Analyzer Operator's Manual. 

Refer to A2000 Service Procedure 35.

The Blank Bag Correction allows for a weight adjustment based on actions that take place during solubilization. The resulting factor adjusts your sample bag weight in an up or downward direction. To determine Blank Bag correction, include at least one empty, sealed and weighed filter bag (blank bag) with your run. After the samples and blank bag have been through the solubilization process and dried as required, divide the final weight of the blank bag by the initial weight. If the samples have been properly prepared, this will result in a factor usually in the 0.992-0.998 range with the F57 filter bag. If the blank bag value is greater than 1.0, refer to question "Why is my blank bag heavier after the run than before the run?"

The MoistureStop Desiccant Pouch is a small, airtight zipper bag, utilized for desiccating all of the Filter Bags that are used with ANKOM instrumentation. A single pouch can hold a full run of F57, F58 or XT4 bags at one time.  When folded, 6 IDF or SDF bags can also be placed into a MoistureStop Desiccant Pouch. Each time a bag has been removed from the desiccant pouch, the air can and should be pushed out. The "zipper" does not have to be used with every bag removal but some action should be taken to keep the air from entering the pouch while the just removed Filter Bag is being weighed. For example, air can be pushed out of the bag by laying it on a firm surface while compressing or flattening the air out of the pouch with your hand.

Many instruments in the marketplace have the capacity to run 6 samples at a time.  After being dried, the beakers, flasks or crucibles are placed into a counter top or cabinet desiccator.  Once cooled, they are then removed one at a time and weighed. Each time the desiccator is opened to remove sample, moist ambient air is introduced inside the desiccator. However, because the lid or door of the desiccator is opened just 6 times, the samples that remain in the desiccator after each item is removed are affected very little by ambient moisture that may be introduced.

However, with Filter Bag Technology, generally larger numbers of Filter Bags are extracted at a time. As with the beakers, flasks and crucibles mentioned above, if the bags are placed in a desiccator after drying, each time the lid or door is opened to remove a bag, moist, ambient air is introduced. Because the desiccator is opened up to 24 times, the moisture can more readily affect the remaining bags. If a collapsible, ANKOM desiccant pouch is utilized, the air can be pushed out of the pouch each time a Filter Bag is removed. This will eliminate a build up of moisture on the remaining Filter Bags and allow for a more accurate and precise result. Every month it is possible to place the small desiccant packets into the oven at 100° - 105°C for a few hours to insure that the desiccant is renewed. In addition, to ensure the integrity of the zip lock bag, regular replacement should be considered.

It is important that the rinse water going into the instrument be at least 50°C for Crude Fiber and 70°C for detergent fibers. For safety purposes, most hot water heaters are set lower than 70°C. In addition, if there is a substantial distance between the instrument and the hot water heater, the rinse water will, at least initially, be even cooler. For these reasons we suggest the purchase of a small hot water heater that can be placed next to the instrument. ANKOM Technology has a small (10 liter) water heater suitable for both the DELTA/DELTAI and the A200/A200I available for purchase.

Rinse water can come directly from the tap. It does not have to be distilled.

It is possible, and may be desirable, to follow an NDF with an ADF using the same sample and Filter Bag. The only drawback is that some samples will produce a lower than expected ADF value when an NDF is run first. The reason for this is that certain components like pectin, tannins, glucans and fructans are removed by NDF solution but not by ADF solution. Therefore, these components are not present in the sample when the ADF follows the NDF. As mentioned above, when you test these types of samples, you will have artificially lower ADF values than you would if you had only run an ADF without the NDF. This issue, of course, has nothing to do with the Filter Bags. They will hold up to both assays with no problem. In fact, you can even follow the ADF with a lignin procedure using the same bags if you wish.

Caution when drying the bags: When running a Lignin procedure or a sequential NDF/ADF or NDF/ADF/Lignin with the F57 Filter Bag, it is important not to dry the bags overnight after the NDF or ADF procedure. A drying timeframe of 2-4 hours at 100° to 105°C is sufficient to thoroughly dry the bags after each procedure. Extended drying times or too high of a temperature can compromise the bag's filtration media.

The F57 filter bag is ash free and therefore can be used for ash determination. See A2000 Service Procedure 34 for the Ashing Procedure.

To prepare the bags, refer to A2000 Service Procedure 33 Ashing Set-up ANKOM F57 & F58 Filter Bags.

Refer to A2000 Service Procedure 32.

To enhance the solution flow through the filter, F58 Filter Bags are made from a hydrophilic material. When exposed to 1N sulfuric acid at high temperatures the material can break at the seams. In addition, with some older bag suspenders, the F58 bags are susceptible to abrasion.

• To minimize breakage at F58 Filter Bag seams, you should use the new F58 bags (as of March 2015). The seams of the new bags are strengthened by the addition of point bonds next to the edge of the seal.
• To minimize bag material abrasion, you should use the new bag suspender (as of March 2015 - part # F11). It has been redesigned to include rounded bottom points on each tray.

When neutral detergent solution gets cold, some of the components will begin to precipitate out of solution. As a result, the solution will turn milky white and particles will be floating in it. These particles can be brought back into solution and the solution cleared by heating it. If the container that holds the NDF solution can fit in a lab oven, it is possible to place the solution in the oven over night at 30°C. If this is not feasible or if you need the solution sooner, pour some of the solution into a beaker and heat the solution on a hot plate or in a microwave. When heated, pour the solution back into the main container to warm up the remaining solution. Repeat until all of the solution is clear with no precipitation.

Neutral detergent consists of varying amounts of 4 dry chemicals and triethylene glycol.
If you remove only a portion of the dry chemicals to make less than 20L of solution, it is impossible to know if the solution has the correct ratio of chemicals.
The only way to ensure that the chemical solution consists of the correct ratio of chemicals is to make all 20L at one time.

Test the rinse water with litmus paper during the last minute of the fourth hot water rinse. If the test indicates the presence of acid, repeat with fresh, hot water until neutral pH is achieved.

As you know, amylase is utilized to help digest the starch in the sample.  Even using expired Alpha Amylase, the non-starch components are undoubtedly gone and probably most of the starch also. 
If you put the filter bags in a 1L beaker with 80^o C water and 8 ml of fresh Alpha Amylase and allow the bags to soak for 20-30 minutes, that should take care of any residual starch.  If you have an A200 Fiber Analyzer, you could put the bags in the bag suspender, place them in the instrument with the heat off (you don’t want boiling water) and turn on the agitation.  After 20-30 minutes rinse the bags once for 5 minutes, dry and weigh.

With the lignin procedure, there are two common errors that will create false high values.

The first error is placing the F57 Filter Bags into the 72% sulfuric acid when there is moisture in the bags and samples. To avoid this situation, once the ADF procedure is complete and the Filter Bags have been dried and weighed, place the Filter Bags back into the oven at 100^o to 105° C for 30 to 60 minutes. When the bags have been dried, place them into a desiccant pouch and allow them to cool to room temperature. Once they have been cooled, immediately place them into the 72% sulfuric acid and begin the procedure.

The second error occurs in the rinsing of the bags after the three-hour soaking in 72% sulfuric acid. It is vital that all of the acid is rinsed out of the bags before the F57’s are placed into the oven for drying. The rinsing process uses copious amounts of fresh water. After several minutes of rinsing, touch several bags with litmus paper. If the litmus paper shows the presence of acid in any of the bags, continue the rinsing for several more minutes and test again. Continue to test the bags with litmus paper until no bags show the presence of acid. At this point, place the bags into a beaker, pour enough acetone to cover the bags and soak for 3 to 5 minutes. When the soaking is complete, pour off the acetone, lay them on a clean surface, and allow the acetone to evaporate from the bags. Place the filter bags into the oven at 100° to 105° C for at least two hours. When the bags have been dried, place them into a desiccant pouch and allow them to cool to room temperature. Once they have been cooled, weigh the bags one final time.
 

During a crude fiber or acid detergent procedure, the time frame during which samples are exposed to 100°C solution(s) is extremely important.  If the fiber analyzer begins a procedure at a temperature higher than 20°C, the instrument will heat the solution too quickly and the effective digestion time frame will be too long.  This will create lower than expected fiber values.  As a result, when performing back-to-back fiber runs with the second being a crude fiber or acid detergent procedure, we would suggest pouring cold water into the vessel prior to the second run in order to cool the instrument to room temperature.