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Chromate Test Strips 3-100 ppm EM Quant (1 PK of 100) HAZMAT fee incl

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Chromate Test Strips 3-100 ppm EM Quant  (1 PK of 100)  HAZMAT fee incl MAIN
MSDS (Material Safety Data Sheet)

EM Quant® Chromate Test, Catalog No. 10012

Test strips and reagent for the detection and semi-quantitative determination of chromate ions


The Chromate Test can be used to monitor waste water discharged from electroplating and pickling plants, tanneries, etc. and for rapidly and reliably determining chromium salts in many industrial processes.

In gravure printing, the Chromate Test can be used to check chromate concentrations in chroming and sensitizing baths to allow optimum values to be maintained. In tanning baths a protective layer of foam prevents the formation of chromate-containing alcohols, which are a hazard to health. The effectiveness of this protective foam layer can be checked with the Chromate Test.

It can also be employed to conjunction with the EM Quant® Nickel Test as a means of rapidly identifying various grades of steel (see Nickel Test).

The Chromate Test may also be used to determine chromium (III) ions, provided that these are oxidized with sodium peroxide or potassium peroxydisulfate, as described under "Note."

Principle of the Method

The basis of the test is a redox reaction between chromate ions and diphenylcarbazide. In an acidic solution, chromate ions oxidize diphenylcarbazide to diphenylcarbazone and this in turn to diphenylcarbadiazone. Chromium(III) ions thus formed react with the enol form of diphenylcarbazone to produce a red-violet complex.


0 - 3 - 10 - 30 - 100mg/l (ppm) CrO42-


  1. Rinse the measuring vessel several times with some of the sample and fill to the 5ml mark.
  2. Add reagent (25% sulfuric acid) dropwise to bring the pH to below 1 (check the pH with pH indicator strips, for instance).
  3. Immerse the reaction zone in the solution for 1 second, remove excess liquid by stroking the edge of the strip against the rim of the vessel, wait 15 seconds and compare the reaction zone with the color scale.


Cr3+ ions can also be determined with the chromate (Cr6+) test if they are oxidized to chromate by the following method:

Add 1 spatula-tip of sodium peroxide or potassium peroxydisulfate to 5ml of solution (pH 5), boil for 5-10 minutes, adjust to below pH 1 with 25% sulfuric acid and make up to ml with water.

1mg/l CrO42- = 0.45mg/l Cr3+ = 1.31mg/l Cr203

Safety Precautions

Keep the reagent (25% sulfuric acid) away from the skin. In the event of contact, rinse well immediately with plenty of water. Seek immediate medical attention of substance enters the eye.

Influence of Anions

The determination is not disturbed by less than 1000mg/l Br-, BrO3-, Cl-, ClO3-, ClO4-, CN-, F-, I-, N3-, NO2-, NO3-, OCN- , PO43-, SCN- , SeO32- , SO42-, S2O82-, WO42-, acetate, citrate, oxalate, succinate or tartrate. [Fe(CN)6]4-, S2-, SO32-, S2O42-, S2O52- and ascorbate reduce CrO4O2- to Cr3+ (see Note).

Interfering colorations are produced by more than

10mg/l IO3- or IO4- (pink to brown)

10mg/l MnO4- (gray-pink)

5mg/l VO3- (brown to ruby colored)

25mg/l molydbdate (pink to violet)

50mg/l [Fe(CN)6]3- (gray to grayish-pink)

Influence of Cations

The determination is not disturbed by less than 1000mg/l Ag+, Al3+, Ba2+, Be2+, Ca2+, Cd2+, Ce3+, Co2+, Cr3+, Mg2+, Mn2+, Ni2+, Ni2+, Rb+, Sr2+, Ti4+, Ti+, Zn2+, or Zr4+

As3+, Fe2+, Sb3+, Sn2+, VO2+ and molybdenum blue reduce CrO42- to Cr3+.

Sparingly soluble lead chromate is formed in the presence of Pb2+; therefore, less or no chromate is detected.

More than 10mg/l Au3+; 100 mg/l Bi3+, Ce4+ or Cu2+; 25 mg/l Fe3+ colors the paper pink or brown.

More than 25mg/l Hg+ or 100mg/l Hg2+ colors the paper blue.

Molybdenum blue interferes with the test due to its intrinsic color.

Elimination of Interference

Proceed as follows with 5ml of the solution to be tested:

IO3-, IO4-: adjust to pH 0-1 with 25% hydrochloric acid, add 1 spatula tip of Titriplex® III and shake well.

Molybdate: adjust to pH 0-1 with 25% hydrochloric acid, add 1 spatula-tip of oxalic acid and shake well.

MnO4-: adjust to pH 0-1 with 25% sulfuric acid and heat to boiling with a few grains of sodium azide. Test for chromate immediately after the solution decolorizes.

[Fe(CN)6]3-: adjust to pH 8-9 with 32% sodium hydroxide solution or 25% sulfuric acid, add 1 spatula-tip of zinc sulfate, shake well, filter, adjust to below pH 1 with 25% sulfuric acid and measure.

Au3+: add 1 spatula-tip of potassium cyanide, shake and adjust the pH to below 1 with 25% hydrochloric acid (in a fume cupboard).

Bi3+: add 1 spatula-tip of Titriplex®III and shake.

Cu2+: fill a glass tube with a diameter of 8-10mm with 2g dry Amberlite® IR-2120 ion exchanger and allow the strong mineral acid solution (pH ~0) to run through dropwise (1 drop/second).

Fe3+: add 20% sodium hydroxide solution until the pH is at least 9, filter and then adjust the pH to below 1 with 25% hydrochloric acid.

Hg+, Hg2+: add 1 spatula-tip of sodium chloride and filter if necessary.

Ce4+: add 1 spatula-tip of potassium fluoride and filter. Check the pH; if necessary, adjust to below 1 with 25% sulfuric acid.

In the presence of As3+, Sb3+, Sn2+, S2-, SO32-, S2O42-, S2O32- or ascorbate,acidify strongly with 25% sulfuric acid (pH~0), add a few crystals of potassium permanganate and boil for approximately 1 minute. Decolorize the hot solution by adding a little sodium azide and shaking. Adjust the pH to less than 1 with 25% sulfuric acid and test immediately for chromate.

Standard (1000 mg/l)

19780 Chromate Standard Solutions, 500ml

Package Size

10012 EM Quant® Chromate Test

Chromate Test for 100 determinations; test strips and reagents included.

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