Hach DR/700 - Page 94

42-10
COPPER, continued
4. Fill two 25-mL
cells to the 25-mL
line with sample.
Note: Wash all
glassware with
detergent. Rinse with
tap water. Rinse again
with Nitric Acid
Solution, 1:1. Rinse a
third time with copper-
free, demineralized
water.
Note: For proof of
accuracy, use a 100 µg/L
copper standard solution
(preparation given in
Accuracy Check) in
place of the sample.
5. Add the contents
of one Copper
Masking Powder
Pillow to one of the
sample cells (the
blank). Cap and
invert several times to
mix.
Note: The other sample
cell is the prepared
sample.
6. Add the contents
of one Porphyrin 1
Reagent Powder
Pillow to each sample
cell. Cap and invert
several times to mix.