Hach DR/700 Procedures Manual page 96

COPPER,
continued
10.
Press: ZERO
The display will count
down to 0. Then the
display will show 0
µg/L and the zero
prompt will turn off.
11.
Place the
prepared sample in
the cell holder.
Note: Typical indoor
lighting permits the
DR/700 to operate with
the cell compartment
open. In bright sunlight,
it may be necessary to
close the cell
compartment cover.
Transfer 10 mL of the
blank and 10 mL of the
sample to 10-mL sample
cell and proceed.
Note: If standards or
samples with high levels
of metal are analyzed, a
slight metallic deposit
or yellow buildup may
appear on the sample
cell wall. Remove by
rinsing with nitric acid.
42-12
12.
Press:
READ
The display will
count down to 0.
Then the display will
show the results in
µg/L copper
(Cu Porphyrin).
Note: For most accurate
results, run the test
using copper-free
demineralized water.
Subtract the value
obtained in Step 12 from
all following tests.
Repeat for each new lot
of reagents.