Hach DR/700 Procedures Manual page 58

GENERAL DIGESDAHL DIGESTION,
7.
Boil off excess
hydrogen peroxide by
heating for one more
minute after addition
of hydrogen peroxide
is complete. Do not
heat to dryness.
Note: If the sample goes
to dryness, turn off the
Digesdahl and cool
completely. Add water
to flask before handling.
Repeat digestion from
the beginning.
REQUIRED REAGENTS
Description
Hydrogen Peroxide, 50%. . . . . 10 mL . . . . . . . 500 mL . . . . . 21196-49
Potassium Hydroxide
Standard Solution, 1 N . . . varies . . . . . . . . 59 SCDB*. . . 23144-26
Potassium Hydroxide
Standard Solution, 8 N . . . . varies . . . . . . . . 500 mL . . . . . . . 282-49
Sulfuric Acid, ACS (concentrated,
specific gravity 1.84) . . . . . ≥3 mL . . . . . . . 4 kg . . . . . . . . . . 979-09
Water, deionized . . . . . . . . . . . varies . . . . . . . . 3.78 L . . . . . . . . 272-17
REQUIRED APPARATUS
Dispenser, pour-out, 10 mL . . . 1. . . . . . . . . . . . each . . . . . . . . 22200-38
Pipet, serological, 10 mL. . . . . 1. . . . . . . . . . . . each . . . . . . . . . . 532-38
Pipet Filler, safety bulb . . . . . . 1. . . . . . . . . . . . each . . . . . . . . 14651-00
Boiling Chips,
silicon carbide. . . . . . . . . . . varies . . . . . . . . 500 g . . . . . . . 20557-34
8.
Take the flask off
the heater and allow
the flask to cool.
Remove the
fractionating column
from the digestion
flask.
Note: Use finger cots to
remove the digestion
flask. Place it on a
cooling pad for at least
one minute. Then
remove the column.
Quantity
Per Digestion Unit
1-40
continued
Cat. No.