Hach DR/850 Procedures Manual page 223

MOLYBDENUM, MOLYBDATE, LR,
Summary of Method
REQUIRED REAGENTS
Molybdenum Reagent Set, 20 mL sample (100 tests) ..................................................24494-00
Includes: (1) 23524-49, (1) 23525-12
Description
Molybdenum 1 Reagent for 20 mL sample size ............1 pillow ............100/pkg .......23524-49
Molybdenum 2 Reagent Solution................................... 0.5 mL .... .50 mL MDB .......23525-12
REQUIRED APPARATUS
Cylinder, mixing, graduated, 25 mL ................................... 1........................each .........1896-40
Sample Cell, 10-20-25 mL, w/cap ...................................... 2......................6/pkg .......24019-06
OPTIONAL REAGENTS
Hydrochloric Acid Solution, 1:1, 6.0 N ................................................... 500 mL ...........884-49
Molybdenum Standard Solution, Ampule
6+
75 mg/L Mo , 2 mL ..............................................................................20/pkg .......25575-20
Molybdenum Standard Solution, 10 mg/L Mo
Sodium Hydroxide Standard Solution, 1.0 N................................. 100 mL MDB .........1045-32
Water, deionized ...............................................................................................4 L ...........272-56
Large interferences are caused by some biocides used in cooling
tower samples. Hach recommends testing the ternary complex
procedure on molybdenum standards containing the specific
biocides in use to determine if the ternary complex method will
work with these samples.
After many samples have been analyzed, the sample cells may
show a slight blue color. Rinse with Hydrochloric Acid Solution,
1:1, to eliminate the build-up.
The ternary complex method for molybdenum determination is a
method in which molybdate molybdenum reacts with an indicator
and sensitizing agent to give a stable blue complex.
6+
..................................... 100 mL .......14187-42
223
continued
Quantity Required
Per Test Unit Cat. No.