LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 126)

ZINC - LOW RANGE
ZINCON METHOD • CODE 3667-SC
QUANTITY CONTENTS CODE
30 mL *Zinc Indicator Solution
*6314-G
120 mL *Methyl Alcohol
*6319-J
10 g Sodium Ascorbate Powder
6316-D
25 g *Zinc Buffer Powder
*6315-G
15 mL *Sodium Cyanide, 10%
*6565-E
30 mL *Formaldehyde Solution, 37%
*5128-G
1 “Dilute Zinc Indicator Solution” Bottle,
with 1 mL pipet assembly
0128-MT
1 Graduated Cylinder, 10 mL, glass
0416
1 Spoon, 0.5 g, plastic
0698
2 Pipets, plain, plastic
0352
1 Spoon, 0.1 g, plastic
0699
*WARNING: Reagents marked with a * are considered hazardous substances.
Material Safety Data Sheets (MSDS) are supplied for these reagents. For your
safety read label and accompanying MSDS before using.
Zinc enters the domestic water supply from the deterioration of galvanized iron
and brass pipes, and from industrial wastes. Zinc is an essential element for
body growth and development and is an important plant nutrient.
Concentrations of zinc above 5.0 mg/L in drinking water can cause a bitter
astringent taste. In the U.S., zinc concentrations may vary between 0.06 to 7.0
mg/L, with an average value of 1.33 mg/L.
APPLICATION:
Drinking and surface waters, domestic and industrial waste
water.
RANGE: 0.00 – 3.00 ppm Zinc
METHOD: Zinc forms a blue colored complex with Zincon in a solution
buffered at pH 9.0. Other heavy metals are complexed by
cyanide and the zinc cyanide complex is released by the
addition of formaldehyde before the other metal cyanide
complexes are destroyed. Sodium ascorbate is added to
reduce the interference of manganese.
SAMPLE
HANDLING &
PRESERVATION: Sample should be analyzed within 6 hours after collection.
The addition of hydrochloric acid will help preserve the
metal ion content, however the acid should be neutralized
before analysis.
COD PLUS TEST PROCEDURES 6/02 ZINC - LOW RANGE 1/3