Hach DR/700 Procedures Manual page 652

ZINC,
continued
4.
Fill a 25-mL
graduated mixing
cylinder to the 20-mL
mark with sample.
Note: For proof of
accuracy, use a 0.5 mg/L
zinc standard solution
(preparation given in
Accuracy Check) in
place of the sample.
Note: Perform the test
using the cells
described. Using
different containers in
Steps 7 and 8 may affect
results.
5.
Add the contents
of one ZincoVer 5
Reagent Powder
Pillow. Cap. Invert
several times until the
powder dissolves
completely.
Note: Inconsistent
readings may result if
all the powder is not
dissolved.
Note: At this point the
sample color should be
orange. If the color is
brown or blue, dilute the
sample and repeat the
test. Either the zinc
concentration is too
high or an interfering
metal is present.
61-96
6.
Measure 10 mL of
the solution into a
10-mL sample cell
(the blank). Cap the
cell.