Chromium Test Papers


Chromate/Chromium Products | CTL Scientific Supply

Chromate / Chromium

Precise rapid tests for water and waste water samples

In the environment, chromium is present only in the form of compounds; the most important natural source is chromite (FeCr2O4). This also serves as starting material for the synthesis of chromium and chromium compounds.

Among other things, chromium is industrially widely used as an alloying element in the field of metal finishing. It is the most important alloying element for the production of stainless and heat-resistant steels. In addition, chromates are used in electroplating (generation of corrosion-resistant chromium coatings), tanneries (suede) and in the paint industry (production of pigment colors).

In industrial wastewaters, trivalent (chromium(III) ions) and hexavalent (chromate and dichromate ions) chromium compounds are found.

Chromates are toxic and carcinogenic. The toxicity of chromium(VI) ions is much higher than that of the chromium(III) ions. However, chromium and its compounds are essential for humans and play a crucial role in the breakdown of glucose in the blood.

Did you know?

Chromium is the most important alloying element for the production of stainless and heat-resistant steels.

Did you know?

Many companies are obliged to control the level of chromate in their effluents.

Our Chromate/Chromium Products

Product Platform Range REF Order
Chromium Test Paper QT > 2 mg/L Cr3+ or > 5 mg/L CrO42- 90724
box of 200 strips $41.60  
QUANTOFIX® Chromate HT 0 · 3 · 10 · 30 · 100 mg/L CrO42- 91301
box of 100 strips & reagent $55.10  
VISOCOLOR® ECO Chromium (VI) CO 0.02 · 0.05 · 0.10 · 0.15 · 0.20 · 0.30 · 0.40 · 0.50 mg/L Cr(VI) 931020
1 kit (~140 tests) $81.90  
NANOCOLOR® Chromate 5 🧪 TT 0.1 - 4.0 mg/L CrO42- 985024
1 pack (20 test tubes) $88.80  
NANOCOLOR® Total Chromium 2 🧪 TT 0.05 - 2.0 mg/L Cr 985059
1 pack (20 test tubes) $133.00  
TT: Tube Tests QT: Qualitative test papers HT: Semi-quanitative test strips CO: Colorimetric test kits TI: Titrimetric test kits PP: Powder Pillows pH: Tests for pH determination

Reaction basis 🧪

  • General: For the determination of total chromium, all oxidation states have to be oxidized to Chromium(VI).
  • Colorimetric and photometric determination is carried out in analogy to APHA 3500-Cr D and DIN 38405-D24.
  • In sulfuric acid, chromate ions react with diphenylcarbazide to form a purple color. Here, the chromate first oxidizes the diphenylcarbazide(I) to diphenylcarbazone(II). At the same time, chromate (cromium(VI)) is reduced to chromium(III). The enol form of the carbazone forms a purple neutral chelate complex with chromium(III) with the molar ratio of chromium:diphenylcarbazone = 1:1.
Chromium Reaction Figure

Sample preservation 🧪

After adjusting the pH with nitric acid to a value of 1–2, the sample can be preserved for storage for up to 1 month (storage vessel: PE or glass bottle).

Chromate samples must be measured quickly within one day. The sample must be cooled.

Did you know?

Chromium(III) ions can be determined by differential measurement of dissolved chromium(VI) ions and total chromium.

Tips & tricks 🧪

  • Background information
    • Detection of chromium(III) ions requires the prior oxidation to chromium(VI). Without decomposition, only dissolved chromium(VI) compounds are detected. To determine chromium(III), total chromium and chromium(VI) are determined. The difference yields the amount of chromium(III) ions. This calculation can be performed only if there are no insoluble chromium(VI) compounds in the sample solution. These are also determined after decomposition only.
  • Sea water suitability
    • Almost all VISOCOLOR® and NANOCOLOR® chromate tests are suitable for sea water analysis. The exception is the standard test NANOCOLOR® total Chromium 2 that does not permit sea water analysis. For more information, please refer to the instruction leaflet.
  • pH
    • The sample solution pH values stated in the instruction leaflets must be complied with. If necessary, adjust the pH with nitric acid or sodium hydroxide.
  • Interferences
    • Coloration, turbidity and larger amounts of organic substances as well as oxidizing or reducing substances interfere with the determination of the tube test NANOCOLOR® Chromate 5 and the standard test NANOCOLOR® Chromate.
    • Chloride interferes with the tube test NANOCOLOR® total Chromium 2 at concentrations above 1000 mg/L.
    • Additional interferences are listed in the respective instruction leaflet.
  • Turbidity
    • Turbid solutions must be filtered prior to the determination of dissolved chromate; turbidity leads to incorrect results: For coarsely dispersed turbidities, use qualitative filter paper (e.g. MN 615), for moderately dispersed turbidities, use glass-fiber paper (e.g. MN 85/70 BF) or or membrane filtration set GF/PET 0.45 μm, for finely dispersed turbidities, use membrane filtration kit 0.45 μm or GF/PET 0.45 μm.
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