Hach DR/700 Procedures Manual page 338

ALUMINUM,
4.
Fill a 50-mL
graduated mixing
cylinder to the 50-mL
mark with sample.
Note: Rinse the cylinder
with 6N (1:1)
hydrochloric acid and
demineralized water
before use to avoid
errors due to
contaminants adsorbed
on the glass.
Note: The sample
temperature must be
o o
20-25 C (68-77 F) for
accurate results.
Note: For proof of
accuracy, use a 0.1 mg/L
aluminum standard
solution (preparation
given in Accuracy
Check) in place of the
sample.
continued
5.
Add the contents
of one ECR Reagent
Powder Pillow.
Stopper and invert
several times to
dissolve the powder;
then wait 30 seconds.
52-12
6.
Add the contents
of one Hexa-
methylenetetramine
Buffer Reagent
Powder Pillow.
Stopper and invert
several times to
dissolve powder.
Note: An orange to
purple color will
develop if aluminum is
present.