What should my hydrolysis blank bag value be? Why would my blank bag value be higher than expected?
What should my hydrolysis blank bag value be? Why would my blank bag value be higher than expected?
If a Mojonnier mixture (pet ether, ethyl ether, ethanol) is utilized, a blank value as high as 0.003g is normal. If pet ether only is used, a blank value as high as 0.001g is normal.
During the hydrolysis phase, fat migration may occur with samples that have fat with low melting points such as triacylglycerides or emulsifiers. Fat loss can be detected by placing a blank bag next to suspect samples in the holder and performing the hydrolysis. If a blank bag loses too much weight during the extraction, this is an indication of fat loss from the neighboring high fat sample during the hydrolysis. We would recommend a greater amount of diatomaceous earth and reduced sample size with any sample that shows this indication of fat loss.
Why do I get Low Values when I hydrolize my high fat samples?
Why do I get Low Values when I hydrolize my high fat samples?
Research with high fat samples has given us the following understandings:
Some samples with fats that have low melting point triacylglycerides or emulsifiers may encounter fat migration during hydrolysis.
To improve fat retention, increase the level of diatomaceous earth (DE) to sample ratio. A ratio of up to 7:1 can be used by reducing the amount of sample and increasing the amount of DE. No more than 1.5g of DE and sample should be placed in each bag.
The increased volume of DE inside the bags will limit the number of samples processed in the Hydrolysis chamber to ten.
Reducing the hydrolysis temperature and time may also improve fat retention.
If, after increasing the DE-to-sample ratio, fat continues to migrate from the bag then a crude fat extraction prior to the hydrolysis may be necessary. By running a crude fat extraction first, the readily available fats are removed before the hydrolysis, but are accounted for. The challenge with this technique is the additional time the process takes.
Fat migration can be detected by placing a blank bag next to suspect samples. Place blank bags next to high fat samples in the holder, and perform the hydrolysis. If a blank bag looses more than 0.0025g of weight during the extraction, this is an indication of fat loss from the neighboring high fat sample during the hydrolysis. Blank bags should always contain at least 0.5g of DE.
Why do I get unexpected High Values when I hydrolize my fat samples?
Why do I get unexpected High Values when I hydrolize my fat samples?
Possible reasons for insufficient drying include:
1) Dryer is not working properly
- Filter needs to be replaced
- Dryer is not heating up to the correct temperature (the dryer controller should be set at 110°C)
2) Samples are not being dried for a long enough time
- All samples should be dried for 3 hours
3) Contaminated rinse water
- The water used for rinsing the sample must be free of contaminants (e.g., salt)
You should place a strip of litmus paper in the desiccant pouch (as noted in the procedure). If the paper shows the presence of acid when the dried XT4 bags are placed inside the pouch, dry the samples for an additional 30 minutes. Repeat this procedure until the acid is gone.