Elcometer 138/2 User Manual page 6

3 TEST PROCEDURE (continued)
3.5 TESTING FOR IRON
1 Remove a test strip from the metal bottle
marked 'Iron Test' and replace the cap on
the bottle immediately.
The test strips included in the kit have a

shelf life determined by the manufacturer.
Before using a test strip, always check
that the expiry date has not been
exceeded. The expiry date is marked on
the test strip container. Further
information concerning the use of test
strips can be found in the manufacturers'
instructions included in the test strip
container.
2 Insert the lower end of the test strip
into the solution (pH 1 to 7, 15°C to
25°C) for 1 second.
3 Remove the test strip from the solution
and shake off excess liquid from the strip.
4 Wait 10 seconds.
5 Compare the test strip with the scale on the metal bottle.
Determine which of the scale colours coincides most exactly with
that of the test strip.
6 Read off the corresponding result in mg/I Fe or, if necessary,
estimate an intermediate value.
For determination of Fe and should any other colour changes occur,
refer to the manufacturers' instructions included with the test strip
container.
Note: The colour of the reaction zone on the test strip may continue to change after
the specified reaction time (10 s) has elapsed. This must not be considered as a
measurement.
If the colour of the reaction zone is equal to or more intense than the darkest
colour on the scale, repeat the measurement using fresh samples diluted with
pure water until a value of less than 500mg/l Fe is obtained. This must then be
multiplied by the corresponding dilution factor.
The reading will be the concentration of iron in 3ml of water. To compare this
reading with that of another collection method, scale the volume of water.
The sample is taken from an area of 12.5cm . To compare with another
collection method, scale the area.
en-5
R
3+
Iron Test
100 Tests
0 3 10 25
mg/l Fe
2+
2+
2
www.elcometer.com
50 100 250 500
2+