YSI 9300 Photometer - Manual (Page 72)

Reagents and Equipment
YSI Iron LR Tablets
YSI 9300 or 9500 Photometer
Round Test Tubes 10 ml glass (PT 595)
Test Procedure
1 Fill the test tube with sample to the 10 ml mark.
2 Add one Iron LR tablet, crush and mix to dissolve.
3 Stand for one minute to allow full color development.
4 Select Phot 18 on photometer.
5 Take photometer reading in usual manner (see photometer instructions).
6 The result is displayed as mg/l Fe.
Iron Complexes
The test color development will normally be complete within one minute.
Continued color development after this time is indicative of more strongly bound
iron complexes in the water. In such cases the test solution should be stood for a
longer period, say 10 - 15 minutes, until color development is complete.
In certain industrial applications strong complexing agents are added to act as
corrosion inhibitors. Moreover, some samples may contain precipitated iron com-
plexes or particles of metallic iron. These samples will require pre-treatment by a
standard laboratory procedure if it is required to determine the total iron content.
The usual method of pre-treatment is acidification-with or without boiling, dep-
ending, on the nature of the sample.
To use the YSI Iron LR test after such pre-treatment procedures, add the Iron LR
tablet to the acidified sample, adjust to pH 3.5 - 4.0 using ammonia or sodium
hydroxide, then take the photometer reading in the normal manner.
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