Hach DR/850, Procedures Manual, Page: 219 / 460

219
Method 8169
MOLYBDENUM, MOLYBDATE, Low Range
(0 to 3.00 mg/L)
Ternary Complex Method
For boiler and cooling tower waters
1.
Enter the stored
program number for
molybdate molybdenum.
Press:
PRGM
The display will show:
PRGM ?
Note: For most accurate
results, perform a Reagent
Blank Correction using
deionized water (see
Section 1).
2.
Press:
47 ENTER
The display will show
mg/L, Mo6 and the
ZERO icon .
Note: For alternate forms
(MoO
4
), press the
CONC key.
3.
Fill a 25-mL mixing
graduated cylinder with
20 mL of the sample.
Note: Filter turbid samples
using the labware listed
under Optional Apparatus.
4.
Add the contents of
one Molybdenum 1
Reagent Powder Pillow
to the graduated
cylinder. Stopper. Invert
the graduated cylinder
several times to dissolve
the reagents.
5.
Pour 10 mL of the
solution into a
sample cell.
6.
Add 0.5 mL of
Molybdenum 2 Reagent
to the sample cell. Swirl
to mix. This is the
prepared sample.
Note: Molybdenum will
cause a green color to form.
7.
Press:
TIMER ENTER
A two-minute reaction
period will begin.
8.
Fill a second sample
cell with 10 mL of
solution from the
graduated cylinder
(the blank).