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Chemical Test Kits
Chromium
1
HI 3845 Chromium Medium Range and
High Range Test Kit
Chromate is determined by a titrimetric
method. Only the hexavalent chromium will
react with iodide in acid solution. (Step 1:)
The amount of iodine generated is
equivalent to the chromium in the sample.
(Step 2:) The liberated iodine is then titrated
with standard sodium thiosulfate solution
that reduces the iodine back to iodide ions.
HI 3845 Chromium
Chromium is a metallic element in the periodic table. It is odorless and tasteless. Chromium
is found naturally in rocks, plants, soil and volcanic dust, humans and animals. The most
common forms of chromium in the environment are trivalent (chromium III), hexavalent
(chromium VI) and the metal form, chromium 0. Chromium III occurs naturally in many
vegetables, fruits, meats, grains and yeast. Chromium VI and 0 are generally produced by
industrial processes. Major sources of chromium VI in drinking water are discharges from
steel and pulp mills, and erosion of natural deposits of chromium III. At many locations,
chromium compounds have been released to the environment via leakage, poor storage, or
improper disposal practices. Chromium compounds are very persistent in water as
sediments. The current maximum contaminant level for chromium in all forms in drinking
water is 100 μg/L, which includes chromium VI.
Toxicologic Information
Hexavalent chromium is transported into cells via the sulfate transport mechanisms, taking
advantage of the similarity of sulfate and chromate with respect to their structure and
charge. Trivalent chromium, which is the more common variety of chromium compounds, is
not transported into cells. Inside the cell, chromium VI is reduced first to metastable
chromium V, then to trivalent chromium. Chromate-dyed textiles or chromate-tanned leather
shoes can cause or exacerbate contact dermatitis. Vitamin C and other reducing agents
combine with chromate to give chromium III products inside the cell. Hexavalent chromium
compounds are genotoxic carcinogens. Chronic inhalation of hexavalent chromium
compounds increases risk of lung cancer (lungs are especially vulnerable, followed by fine
capillaries in kidneys and the intestine). According to some researchers, the damage is
caused by hydroxyl radicals, produced during reoxidation of pentavalent chromium by
hydrogen peroxide molecules present in the cell. In the U.S., the OSHA PEL for airborne
exposures to hexavalent chromium is 5 µg/m3 (0.005 mg/m3).
Chromium salts are widely used in industrial processes, such as metal finishing and plating
industries, as well as in the leather industry as a tanning agent, and in the manufacture of
paints, dyes, explosives and ceramics. Chromium may enter a water supply through the
discharge of waste from these industries and may also be discharged from chromate-treated
cooling waters, where they are frequently added for corrosion control. The hexavalent state
of chromium is toxic to humans, animals and aquatic life. It can also produce lung tumors
when inhaled and readily induces skin sensitization.
METHOD
RANGE
SMALLEST
INCREMENT
CHEMICAL
METHOD
5 mg/L (ppm)
50 mg/L (ppm)
iodometric
# TESTS WEIGHT
HI 3845 Chromium (as Cr6+)
titration
0-100 mg/L (ppm)
100-1000 mg/L (ppm)
100 avg.
416 g
HI 3846 Chromium (as Cr6+)
colorimetric
0.0-1.0 mg/L (ppm)
0.2 mg/L (ppm)
www.hannainst.com
diphenylcarbohydrazide
100 avg.
160 g
Step 1:
2(CrO4)2- + 16H+ + 6I— 3I2 + 8H2O + 2Cr3+
Step 2:
I2 + 2(S2O3)2– 2I— + (S4O6)2-
HI 3846 Chromium Test Kit
Chromium VI reacts with diphenylcarbohydrazide to form a purple product in
an acidic buffered condition. The amount of
color developed is proportional to the
concentration of chromium present in the
aqueous sample.
HI 3846 Chromium
ORDERING INFORMATION
HI 3845 test kit comes with chromium MR-HR
reagent A (100 packets), 17 g chromium MR-HR
reagent B, 60 mL chromium MR-HR reagent C,
25 mL starch indicator, 20 mL calibrated vessel,
1 mL plastic pipette, graduated plastic test tube
with cap.
HI 3846 test kit comes with HI 3846-0 reagent (100
packets) and color comparison cube.
HANNA CHECKER®HC SERIES AND CHEMICAL TEST KITS
The HANNA chromium test kit is field
portable and can also be used in the
laboratory. HI 3845 is able to determine
traces of chromium up to 1000 ppm.
ACCESSORIES
HI 3845
HI 3845-100
HI 3846
HI 3846-100
Spare reagent for 100 tests
Spare reagent for 100 tests
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