YSI 9300 Photometer - Manual (Page 31)

PHOTOMETER TEST INSTRUCTIONS
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Aluminum sulphate is widely used as a coagulant in drinking water treatment.
The determination of aluminum (residual alum) is usually required for the
control of alum coagulation and filtration processes at water works.
Aluminum salts are found in natural waters; levels are reported to be increasing
particularly in areas affected by acid rain. High aluminum levels can be toxic to fish
and aquatic life. Aluminum determination is necessary therefore for environmental
control and for testing water used for fish farms, etc.
The YSI Aluminum test provides a simple method of measuring aluminum levels
in natural and drinking waters over the range 0 - 0.5 mg/l.
Method
Aluminum reacts with Eriochrome Cyanine R indicator in slightly acid solution to
produce a pink-red colored complex. The presence of ascorbic acid eliminates
interference from iron and manganese. In the YSI Aluminum method the
necessary reagents are incorporated into two test tablets. The test is simply
carried out by adding one of each tablet to a sample of the water. The first
tablet acidifies the sample to bring any colloidal aluminum into solution and the
second tablet buffers the solution to provide the correct conditions for the test.
The intensity of the color produced in the test is proportional to the aluminum
concentration and is measured using a YSI Photometer.
Reagents and Equipment
YSI Aluminum No 1 Tablets
YSI Aluminum No 2 Tablets
YSI 9300 or 9500 Photometer
YSI Photometer Round Test Tubes, 10 ml glass (PT 595)
Photometer Method
AUTOMATIC
WAVELENGTH
SELECTION
0 – 0.5 mg/l
PHOT.3.AUTO