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Chromate (hexavalent) Test Kits

Chromate (hexavalent) Test Kits

What is Hexavalent Chromium (Chromate)?
Chromium (Cr) is a naturally occurring metal that can be found in soil and ground waters. It is a nonessential trace element for plant health but essential for animal health. The common forms of chromium are trivalent chromium, Cr(III), and hexavalent chromium, Cr(VI). In the environment, hexavalent chromium occurs mostly as chromate ion (CrO42-). Chromium salts are used in numerous industrial processes including electroplating and the manufacture of pigments and paints. Historically, chromate was used extensively as a corrosion inhibitor in open and closed cooling water systems, however alternative inhibitors have superseded chromate due to environmental and public health concerns related to Cr VI discharges.

Why Test for Chromate?
Chromate is often measured in water after industrial processes to ensure it is within pollution limits. In open and closed cooling systems, chromate is measured to ensure that the correct amount of chemical is being dosed to inhibit corrosion but not so much that it is being wasted.

About Our Test Kits
CHEMetrics offers both visual and instrumental test kits for the measurement of chromate in water. These test kits do not measure trivalent chromium.

The CHEMets® visual colorimetric test kit turns a red-violet color in direct proportion to the hexavalent chromium concentration. Measurements are made against a color comparator. Results are expressed as ppm (mg/L) CrO4.

The Vacu-vials® instrumental colorimetric test kit also turns a red-violet color and requires the use of a  CHEMetrics direct-readout photometer or spectrophotometer capable of accepting a 13-mm diameter round cell.

Click on a catalog number in the tables below for more information or to purchase a test kit.

Visual Kits

Range MDL Method Kit Catalog No. Refill Catalog No.
0-1 & 1-10 ppm 0.05 ppm Diphenylcarbazide K-2810 R-2810

Instrumental Kits

Range Method Kit Catalog No.
0-3.50 ppm Diphenylcarbazide K-2803

Method

The Diphenylcarbazide Method

References: APHA Standard Methods, 23rd ed., Method 3500-Cr  B- 2009. ASTM D 1687-02, Chromium in Water, Test Method A.
With the chromate test method, hexavalent chromium reacts with diphenylcarbazide under acid conditions to form a red-violet color. Results are expressed as ppm (mg/L) CrO4.