LaMotte DC1600 Colorimeter - Manual (Page 89)

ZINC
ZINCON METHOD CODE 3667
QUANTITY CONTENTS CODE
30 mL *Zinc Indicator Solution *6314-G
100 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” 0128-MT
Bottle, with 1 mL pipet assembly
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: 0.0 – 3.0 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.
INTERFERENCES: The following ions interfere in concentrations greater than those listed.
ION mg/L
Cd(II) 1
Al(III) 5
Mn(II) 5
Fe(III) 7
Fe(II) 9
Cr(III) 10
Ni(II) 20
Cn(II) 30
CrO
4
(II) 50
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