Hach DR/700 Procedures Manual page 286

NITRATE, LR,
4.
Fill a 50-mL
graduated mixing
cylinder to the 30-mL
line with sample.
Note: For proof of
accuracy, use a 0.20 mg/L
nitrate nitrogen standard
solution (preparation
given in Accuracy
Check) in place of the
sample.
continued
5.
Add the contents
of one NitraVer 6
Nitrate Reagent
Powder Pillow to the
cylinder. Stopper.
50-36
3 minutes
6.
Shake the cylinder
continuously for three
minutes.
Note: A deposit of
unoxidized metal will
remain after the
NitraVer 6 Nitrate
Reagent Powder
dissolves. This is
normal and will not
affect test results.
Note: Shaking time and
technique influence
color development. For
most accurate results,
make successive tests on
a solution containing a
known amount of nitrate
and adjust the shaking
time to obtain the
correct results. See
Accuracy Check for
more information.