YSI 9300 Photometer - Manual (Page 120)

PHOTOMETER TEST INSTRUCTIONS
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Pure water exhibits a light blue color when viewed in depth. This color may be
modified by the presence of organic material, typically to a yellow or brown
color. An estimate of this color intensity is used as a simple means of monitoring
natural and treated water.
Method
The color of the water is determined photoelectrically using the YSI Photometer.
The sample should be filtered to remove suspended solids before analysis to
determine the 'true color' due to dissolved matter.
The color of water is expressed using the platinum/cobalt color scale (Pt/Co
scale). Each unit is equivalent to the color produced by 1 mg/l platinum in the
form of chloroplatinic acid in the presence of 2 mg/l cobaltous chloride
hexahydrate. These units are identical with 'Hazen' units, which have been
traditionally used to express results from the visual estimation of water color.
Reagents and Equipment
YSI Color/Turbidity Set (PM 269)
YSI 9300 or 9500 Photometer
Photometer Method
AUTOMATIC
WAVELENGTH
SELECTION
10 – 500 mg/l Pt
(10 – 500 mg/l Hazen Units)
PHOT.47.AUTO