Iron Test Strips 3-500 ppm EM Quant (1 PK of 100)

Purchase Iron Test Strips 3-500 ppm EM Quant (1 PK of 100)

MSDS (Material Safety Data Sheet)

EM Quant^® Iron Test, Catalog No. 10004

Test strips and reagent for the detection and semi-quantitative determination of iron(II) ions

General

The test strips offer a very simple means of determining iron in all aqueous media and on metal surfaces. They can thus be used to distinguish between ferrous and non-ferrous metals.

Applications of interest include the analysis of foodstuffs such as wine, fruit juices, vegetable juices, mineral water, canned goods and preserve liquids.

In wine analysis, preliminary testing with the Iron Test will show whether treatment with potassium hexacyanoferrate(II) is necessary.

A special use for the Iron Test is to be found in gravure printing, for checking etching baths. The Iron Test is considerably quicker than the titration method for checking the efficiency of iron chloride etching baths.

The test strips are also ideally suited for checking the use (control and optimization) of iron compounds as flocculating agents in waste water treatment, as they cover the permitted discharge limits.

Principle of the Method

Iron(II) combines with 2,2'-bipyridine to form a dark red complex. The special advantage of this test is that it contains a buffer which, for sample solutions with a pH of between 1 and 7, makes complexation in the paper independent of the pH.

Only iron(II) is detected. Any iron(III) present can be simply and rapidly reduced to iron(II) with ascorbic acid. Following reduction, the test strip shows the total quantity of iron(II) and iron(III) present.

Graduation

0 - 3 - 10 - 25 - 50 - 100 - 250 - 500 mg/l (ppm) Fe²⁺

Directions

Immerse the test strip in the sample solution for 1 second so that the reaction zone is thoroughly moistened.
Remove the test strip, gently shake off any excess liquid, wait 10 seconds and compare the reaction zone with the color scale.

Notes

The sample solution should have a pH between 1 and 7.

Strongly acidic solutions (pH less than 1) must be buffered with sodium acetate; solutions above pH 7 with sulfuric acid.

Fe2+ ions are determined by dissolving one spatula-tip of ascorbic acid in approximately 10 ml of sample solution and waiting 10-15 seconds before measuring the iron concentration. Iron(II) and iron(III) ion concentrations can be determined separately by calculating the difference between the results obtained before and after reduction.

At above pH 2-3, the quantity of dissolved iron(III) decreases so that iron(III) is no longer detected.

Iron determination in etching baths (Fogra method)

Pipette exactly 1ml of the original etching bath into a 1-liter volumetric flask, add approximately 3ml of 85% phosphoric acid and make up to 1 liter with distilled water. Immerse a EM Quant^®test strip in this dilute solution and compare the color of the reaction zone with the color scale.

Since the dilution is 1:1000, the value read from the color scale in mg/l can be taken as being g/l Fe²⁺ in the etching bath. Multiplying the iron concentration in g/l by a factor of 0.57 gives, in g/l Cu²⁺, the amount of copper (also present in the etching bath) that is equivalent to the divalent iron content. Alternatively, the EM Quant^® Copper Test can be used to determine copper directly.

Influence of Anions

There is no interference at less than:

1000mg/l	Br^–, BrO₃^–, Cl^–, ClO₃^–, ClO₄^–, CN^–, CrO₄^2–, F^–, I^–, IO₃^–, MnO₄^–, Mo₇O₂₄^6–, N^3–, NO₂^–, NO₃^–, OCN^–, PO₄^3–, SCN^–, SO₃^2–, SO₄^2–, S₂O₃^2–, S₂O₄^2– S₂O₅^2–, S₂O₈^2–, SeO₃^2–, WO₃^2– , acetate, ascorbate, citrate, oxalate succinate or tartrate.
250mg/l	F^–, N^3–, S₂O₅^2–, WO₄^2–

[Fe(CN)₆]³⁺ and [Fe(CN)₆]^4- sequester iron.

Influence of Cations

There is no interference at less than:

1000mg/l

Ag⁺, Al³⁺, As³⁺, Au³⁺, Ba²⁺, Be²⁺, Bi³⁺, Ca²⁺, Cd²⁺, Ce⁴⁺, Cr³⁺, Hg⁺, Hg²⁺, K⁺,Li⁺ Mg²⁺, Mn²⁺, NH⁴⁺, Na⁺, Ni²⁺, Pb²⁺, Rb⁺, Sb³⁺, Sn²⁺, Sr²⁺, Tl⁺, Ti⁴⁺, Zn²⁺, Zr⁴⁺

Elimination of Interference

If the color of the reaction zone differs from the color scale, it can be assumed that foreign ions are interfering. To prevent this, add 1 spatula-tip of the masking agent specified in the table below to approximately 5ml of sample solution, shake for 1-2 minutes and then test for iron ions with a test strip.

In the presence

Color of more than mask with

orange 250mg/l Co²⁺ cadmium

violet 500mg/l Cu²⁺ cadmium

blue molybdenum blue cadmium

brown 250mg/l VO₂⁺ hydroxylammonium chloride

[Fe(CN)₆]³⁺ and [Fe(CN)₆]^4- sequester iron and prevent its detection. Complexed iron can be detected in the usual way after fuming off with concentrated sulfuric acid.