Applicable Samples :Soils. Sludges, Sediments & other similar waste materials

Weigh a small amount of sample in a beaker.

Add 50 ml of solution ( Magnesium Choride in 1M Phosphate buffer ).

Cover beaker with watch glass. Then stir for 5 minutes.

Heat mixture on a water bath at 90-95oC for atleast 60 minutes with continuous stirring.

Cool mixture to room Temperature with constant stirring.

Filter thru a 0.45 microns filter paper.

Adjust filtrate to appropriate pH using 5M Nitric acid.

Transfer 95 ml of this solution to a 100ml volumetric flask.

Add diphenylcarbazide.

Adjust to appropriate pH using using Sulfuric acid then dilute to the mark.

Invert several times to mix.

Let stand for 5 to 10 minutes for full color development.

Read absorbance of solution at 540 nm using 1 cm cuvette.

Read absorbances of atleast 3 the standard solutions of Chromium 6+.

Prepare calibration curve from absorbance readings of standard solutions against their corresponding concentrations.

Calculate the Hexavalent Chromium content using Linear regression.

Related Posts :
IEC 62321 – Hexavalent Chromium Testing Method & Procedure
EN 71 Part 3 ( Testing Procedure )
Hexavalent Chromium ( Cr6+) in Water
IEC 62321 – Lead, Cadmium & Mercury Testing Method & Procedure
ASTM F963 -96a / ASTM F963 -07 (Testing Procedure)