Hach DR/700 - Page 558

61-2
BORON, continued
4. Accurately pipet
2.0 mL of sample into
another 125-mL
erlenmeyer flask (the
prepared sample).
Note: For proof of
accuracy, use a 4.0 mg/L
boron standard solution
(preparation given in
Accuracy Check) in
place of the sample.
Warning: Do not use a
stoppered or capped
vessel to complete Steps
4 and 5.
5. Add 35 mL of the
BoroVer 3-sulfuric
acid solution to each
erlenmeyer flask
using a 50-mL
graduated cylinder.
Swirl to mix
completely.
6. Wait 25 minutes.
7. Install module
61.01
in a DR/700.
8. Press: I/O
The display will show
610 nm
and module number
61.01
9. After 2 seconds,
the display will show
a program number,
the concentration
units and the zero
prompt. If necessary,
press the
UP ARROW
key until the lower
display shows
program number
61.01.1
25 minutes