YSI 9300 Photometer - Manual (Page 74)

Test Procedure
1 Fill test tube with sample to the 10 ml mark.
2 Add one Iron HR tablet, crush and mix to dissolve.
3 Stand for one minute to allow full color development.
4 Select Phot 19 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 completed within one minute. Con-
tinued 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 HR test after such pre-treatment procedures, add the Iron
HR tablet to the acidified sample, adjust to pH 6.0 - 9.0 using ammonia or
sodium hydroxide, then take the photometer reading in the normal manner.
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