Hach 59530-16, Instruction Manual

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Iron, Total,
continued
The following do not interfere with the test when present up to the levels listed:
Summary of Method
The TPTZ Iron Reagent forms a deep blue-purple color with ferrous iron. The
indicator is combined with a reducing agent which converts precipitated or
suspended iron, such as rust, to the ferrous state. The amount of ferric iron present
can be determined as the difference between the results of a ferrous iron test and
the concentration of total iron.
Element Interference level Element Interference level
Cadmium 4.0 mg/L Manganese 50.0 mg/L
Chromium
(3+)
0.25 mg/L Mercury 0.4 mg/L
Chromium
(6+)
1.2 mg/L Molybdenum 4.0 mg/L
Cobalt 0.05 mg/L Nickel 1.0 mg/L
Copper 0.6 mg/L Nitrite Ion 0.8 mg/L
Cyanide 2.8 mg/L