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RES: RES: RES: [compost_tea] Humic Acid
On the contrary. Fulvic acids are defined as the portion
soluble over a wide range of pHs according to a report to
the US Government I got and yes there are several methods for
their extraction and measurement.
They separate both by first making humic acids go into
solution by using an alcaline agent like NaOH, KOH or ammonia salts.
After they got all humic acid in solution ( note that they are only
soluble at high pH) they will then lower the pH causing Humic to
precipitate.
What is left in solution after lowering the pH is accounted as fulvic
acid
and what has precipitated is accounted as humic.
You can find virtually dozens of extraction methods but they basic
perform
as explained above.
Just do a search in the USPTO and see how many patents are there.
Jose
There is no standard assay for fulvic acid, to my knowledge at this
time.
Fulvic Acid has been defined as the portion of humic acids that are
soluable
at Ph of 2. They are also soluble at higher pH's.
The CA method, I believe, takes a sample and lowers the pH and measures
the
parcipitates. The short chain humic acids (fulvics) remain in solution
and
therefore, go uncounted. That is why the numbers are always smaller than
the
A&L technique. I am not sure of the exact procedure but by looking at
the
results from the two tests, you can get an indication of the relative
percentage of short and longer chain molecules in the sample.
Tom
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