Hach DR/700 Procedures Manual page 457

CHROMIUM, HEXAVALENT,
INTERFERENCES
The following do not interfere in the test up to the following concentration:
Mercurous & Mercuric Ions
Iron
Vanadium
Vanadium interference can be overcome by waiting ten minutes before
reading.
Highly buffered samples or extreme sample pH may exceed the
buffering capacity of the reagents and require sample pretreatment; see
Interferences, pH (Section I).
SUMMARY OF METHOD
Hexavalent chromium is determined by the 1,5-diphenylcarbohydrazide
method using a single dry powder formulation called ChromaVer 3
Chromium Reagent. This reagent contains an acidic buffer combined
with 1,5-diphenylcarbohydrazide, which reacts to give a purple color
when hexavalent chromium is present.
REQUIRED REAGENTS AND APPARATUS
(Using Powder Pillows)
Description
ChromaVer 3 Chromium
Reagent Powder Pillows,
for 5 and 10-mL samples . . 1 pillow . . . . 50/pkg . . . . . . . . 12710-99
Clippers, for opening
powder pillows . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . . . 968-00
DR/700 Filter Module
Number 55.01. . . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . 46255-00
REQUIRED REAGENTS AND APPARATUS
(Using AccuVac Ampuls)
ChromaVer 3
AccuVac ampuls . . . . . . . . 1 ampul . . . . 5/pkg . . . . . . . . . 25050-25
Adapter, AccuVac Vial . . . . . . 1 . . . . . . . . . each . . . . . . . . . . 46025-00
Beaker, 50 mL . . . . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . . . 500-41
DR/700 Filter Module
Number 55.01. . . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . 46255-00
continued
Interfere slightly
1 mg/L
1 mg/L
Quantity
Per Test Unit
55-9
Cat. No.