Hach DR/700 Procedures Manual page 229

SULFATE,
continued
4.
Prepare the
displayed standard.
For each mg/L
displayed, pipet
1.00 mL of 1000
mg/L of Sulfate
Standard Solution
into a 1000-mL
volumetric flask. Add
demineralized water
to the mark. Cap and
invert 10 times to
mix.
Note: For example: to
make a 50 mg/L
standard, pipet 50.0 mL
into the flask, For a
zero concentration
standard, use only
demineralized water.
5.
Pour at least 40
mL of the displayed
standard into a
50-mL beaker.
45-57
6.
Collect at least
40 mL of sample in a
50-mL beaker.
Note: Filter highly
colored or turbid
samples. Use labware
listed under
Optional Apparatus.