Iron, Total
Iron, Total
IronTot_AVPP_Other_TPT_Eng_Ody.fm Page 3 of 6
Interferences
Interference tests were performed using an iron concentration of 0.5 mg/L.
When interferences occurred, the color formation was inhibited or a precipitate
formed. The following do not interfere with the test when present up to the
levels given.
5. Touch the timer icon.
Touch
OK.
A three-minute reaction
period will begin.
Complete step 6 during
this period.
6. When the timer
beeps, place the blank
into the adapter.
7. Touch Zero.
The display will show:
0.000 mg/L Fe
8. Place the prepared
sample into the adapter.
Touch
Read.
Results will appear in
mg/L Fe.
10 mL
20 mL
25 mL
Zero
Interfering Substance Interference Levels and Treatments
Cadmium 4.0 mg/L
Chromium (
3+
) 0.25 mg/L
Chromium (
6+
) 1.2 mg/L
Cobalt 0.05 mg/L
Copper 0.6 mg/L
Cyanide 2.8 mg/
Manganese 50.0 mg/L
Mercury 0.4 mg/L
Molybdenum 4.0 mg/L
Nickel 1.0 mg/L
Nitrite Ion 0.8 mg/L
Color or turbidity
In the powder pillow procedure, if the sample, without a TPTZ Iron Reagent Powder Pillow, has a
color or turbidity greater than the blank (deionized water plus TPTZ Iron Reagent), then use the
sample as the blank.
pH
A sample pH of less than 3 or greater than 4 after the addition of reagent may inhibit color
formation, cause the developed color to fade quickly, or to result in turbidity. Adjust the sample
pH in the sample cell before the addition of reagent to between 3 and 4 by using a pH meter or pH
paper and adding dropwise an appropriate amount of iron-free acid or base such as 1.0 N
Sulfuric Acid Standard Solution (Cat. No. 1270-32) or 1.0 N Sodium Hydroxide Standard
Solution (Cat. No. 1045-32). Make a volume correction if significant volumes of acid or base are
used; see Section 3.1.3 Correcting for Volume Additions on page 29.
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