Hach DR/700 Procedures Manual page 61

Table 8. Digestion Guidelines for Specific Sample Types
Sample Sample
Type Weight
Plant 0.25 to 5 g
Tissue
Meat & 0.5 g or
Poultry predigestion
Fluid 0.1 to 0.25 g
Fertilizers
Feed & 0.25 g
Forage
Dairy 0.25 to 2.0 g
Cereal 0.25 to 0.5 g
Beverage approx. 5 g
(pipet into
funnel)
Sludge < 2.5 g wet
sludge
< 0.5 g dried
sludge
Water & not more than 3 mL
Waste- 0.5 g solid
water (mL = 50/C;
C = % solids)
Bath 0.3 to 10 mL
Solutions
Amount Preheat
of Acid Time
4 mL 4 min.
4 mL or as 4 min.
in predigest
4 mL 4 min.
4 mL 4 min.
4 mL 4 min.
4 mL 4 min.
4 mL 1 min.
4 mL 3 to
5 min.
until acid
is refluxing increase in
4 mL 4 minutes 10 mL
1-43
Amount of Special
Peroxide Instructions
10 mL Use N-free paper
to weigh sample
10 mL May use
predigestion
procedure; see
Systems for Food,
Feed and
Beverage Analysis
(Lit. Code 3120.)
10 mL Add 0.4 g Kjeldahl
Reduction Powder
to flask before
adding sulfuric
acid. Place the
flask in an 80 °C
oven 15 minutes
before digestion.
Use N-free paper to
weigh sample
10 mL Use N-free
paper to weigh
sample
10 mL Use N-free paper
to weigh dry
samples (cheese)
10 mL Use N-free paper to
weigh sample
10 mL Preheat acid for 1
minute then add
sample through
funnel. Heat flask
30 seconds after
sample is in flask.
10 mL or Heat the diluted
increase in digest for 15
5 mL minutes and filter.
increments
10 mL or Water must
evaporate before
5 mL acid will reflux.
increments Boiling chips
required.
Water must
evaporate before
acid will reflux.
Boiling chips
required.