YSI 9300 Photometer - Manual (Page 75)

PHOTOMETER TEST INSTRUCTIONS
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Manganese-containing minerals occur widely and manganese salts are
commonly found in many natural waters. Manganese is an objectionable
constituent in water used for domestic purposes or industrial applications. In
domestic situations, manganese will cause brown or black staining to laundry or
plumbing fittings even at very low concentrations. In process applications such
as paper manufacturing or textile finishing similar staining can occur.
Manganese salts may impart an astringent taste to drinking water supplies, and
in swimming pool applications can give an aesthetically displeasing brown
coloration to the water.
In most cases where manganese salts occur naturally in the water, it will be
necessary to apply special methods of removal before the water can be used for
domestic or industrial purposes. The YSI Manganese test provides an extremely
sensitive method of measuring low concentrations of manganese for the
assessment of natural waters and the control of manganese removal plant. The
test measures total manganese over the range 0 - 0.030 mg/l.
Method
Manganese may occur in water in various different valency states. In the first
stage of the YSI method, manganese in lower valency states is oxidised to form
permanganate by the action of an oxidising agent. In the second stage the per-
manganate formed is further reacted with leucomalachite green to form an
intense turquoise colored complex. Catalysts and inhibitors are incorporated into
the tablet reagents to ensure that the color reaction proceeds correctly and
interferences are eliminated.
The intensity of color produced in the test is proportional to the total manganese
concentration and is measured using a YSI Photometer.
Photometer Method
AUTOMATIC
WAVELENGTH
SELECTION
0 – 0.030 mg/l
PHOT.20.AUTO