YSI 9300 Photometer - Manual (Page 100)

PHOTOMETER TEST INSTRUCTIONS
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Oxygen is a major cause of corrosion in boilers and steam raising plant. Sodium
sulfite and catalysed sulphite formulations are extensively used as oxygen
scavengers in boiler water treatment.
The YSI Sulfitest test provides a simple means of measuring sulfite levels for the
control of such treatments in boiler plant. The test covers the range 0 - 500
mg/l Na
2
SO
3
.
Method
The YSI Sulfitest method is based on a colorimetric procedure involving the
reduction of an indicator dye. Sulfites react with the indicator dye under
buffered conditions to destroy the original purple coloration. With increasing
sulfite concentrations a range of colors from purple to colorless is produced.
An advantage of the Sulfitest method is that it does not respond to other
reducing species as do traditional iodometric methods.
The degree of color loss observed in the test is proportional to the sulfite
concentration and is measured using a YSI Photometer.
Reagents and Equipment
YSI Sulfitest No 1 Tablets
YSI Sulfitest No 2 Tablets
YSI 9300 or 9500 Photometer
Round Test Tubes, 10 ml glass (PT 595)
Photometer Method
AUTOMATIC
WAVELENGTH
SELECTION
0 – 500 mg/l Na
2
SO
3
PHOT.34.AUTO