33
TKN, Colorimetric Methods
Consult the spectrophotometer or colorimeter procedure to complete the
TKN analysis. The following is only a guide to use if a procedure is
not available.
1. Pipet an appropriate analysis volume into a graduated mixing cylinder.
2. Add one drop of TKN Indicator.
3. Add one drop of 8 N KOH Standard Solution, swirling between each
addition, until the first flash of pale blue appears (pH 3).
4. Add one drop of 1 N KOH. Stopper the cylinder and invert several
times to mix.
Note: View the cylinder from the top against a white background. Compare the
cylinder against a second cylinder filled to the same volume with deionized water.
5. Continue to add 1 N KOH in this manner until the first permanent blue
color appears.
6. Add deionized water to the volume indicated in the colorimetric
procedure.
7. Continue with the colorimetric procedure.
GENERAL DIGESDAHL DIGESTION, continued
网址：www.mamots.com 电话：0431-85178766
To Next Page
Loading...
