Hach DR/700 Procedures Manual page 194

COLOR, TRUE AND APPARENT,
SUMMARY OF METHOD
Color may be expressed as "apparent" or "true" color. The apparent
color includes that from dissolved materials plus that from suspended
matter. By filtering or centrifuging out the suspended materials, the true
color can be determined. The procedure describes true color analysis. If
apparent color is desired, it can be determined by measuring an
unfiltered water sample. The stored program is used for both forms of
color.
The stored program is calibrated in color units based on the APHA-
recommended standard of 1 color unit being equal to 1 mg/L platinum
as chloroplatinate ion.
REQUIRED REAGENTS
Description
Water, demineralized . . . . . . . 50 mL . . . . . 4 L . . . . . . . . . . . . 272-56
REQUIRED APPARATUS
Aspirator, vacuum . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . . 2131-00
DR/700 Filter Module
Number 45.01. . . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . 46245-00
Filter Holder, 47 mm,
300 mL graduated . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . 13529-00
Filter, membrane, 47 mm,
0.45 microns . . . . . . . . . . . 1 . . . . . . . . . 100/pkg . . . . . . . 13530-00
Flask, filtering, 500 mL . . . . . 1 . . . . . . . . . each . . . . . . . . . . . . 546-49
Stopper, No 7, one hole . . . . . 1 . . . . . . . . . 6/pkg . . . . . . . . . . 2119-07
Tubing, rubber . . . . . . . . . . . . 1 . . . . . . . . . 12 ft . . . . . . . . . . . 560-19
OPTIONAL REAGENTS
Color Standard Solution,
500 platinum-cobalt units . . . . . . . . . . . . 1 L . . . . . . . . . . . . 1414-53
OPTIONAL APPARATUS
Cap for 10- and 25-mL sample cells . . . . . . . 12/pkg . . . . . . . . 24018-12
Cylinder, graduated, 50 mL. . . . . . . . . . . . . . each . . . . . . . . . . . 1081-41
Flask, volumetric, Class A, 100 mL . . . . . . . each . . . . . . . . . . 14574-42
Pipet, volumetric, Class A, 50 mL . . . . . . . . each . . . . . . . . . . 14515-41
Sample Cell, 10-mL with screw cap . . . . . . . 6/pkg . . . . . . . . . 24276-06
Quantity
Per Test Units
45-22
continued
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