LaMotte SMART 2 - Manual (Page 115)

CHROMIUM–HEXAVALENT,
TRIVALENT & TOTAL
DIPHENYLCARBOHYDRAZIDE METHOD • CODE 3698-SC
QUANTITY CONTENTS CODE
60 mL *Sulfuric Acid, 5N *7681-H
10 g *Chromium Reagent Powder *V-6276-D
15 mL *Sodium Azide, 5% *7683-E
30 mL Potassium Permanganate, 0.5% 7682-G
60 mL Deionized Water 5115PT-H
1 Pipet, plain, glass, w/cap 0341
1 Pipet, 1.0 mL, plastic 0354
1 Spoon, 0.1 g, plastic 0699
1 Graduated Cylinder, 50 mL, glass 0418
1 Erlenmeyer Flask, 125 mL, glass 0431
1 Test tube holder 1113
1 Filter Paper 0465
1 Funnel, Plastic 0459
*WARNING: Reagents marked with an * are considered to be potential health
hazards. To view or print a Material Safety Data Sheet (MSDS) for these reagents go to
www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or fax.
A toxic chemical, chromium is found in two forms in the water; trivalent
chromium (Cr
3+ ) and hexavalent chromium (Cr 6+ ). Chromium enters the
water from industrial waste. Hexavalent chromium is more toxic than trivalent
chromium. Levels greater than 0.5 ppm indicate improperly treated industrial
waste. It is important to maintain chromium levels at or below 0.5 ppm,
because clams and other shellfish will store chromium in their systems,
accumulating levels which may be dangerous to the consumer, whether human
or animal.
APPLICATION: Drinking, surface, & saline water; domestic and industrial
waste.
RANGE: 0.00–1.00 Chromium
METHOD: The trivalent chromium is converted to hexavalent
chromium by permanganate under acidic conditions.
Hexavalent chromium reacts with 1,5
diphenylcarbohydrazide under acidic conditions to form a
red-purple color in proportion to the amount of chromium
present.
Smart2 TEST PROCEDURES 10.04 Chromium–Hexavalent, Trivalent & Total 1/4