BYK LCM III Mode D'emploi page 35

Standard Operations
5.5.2 Determine the Iodine color value
5.5.3 Determine the Hazen color value (Pt-Co or APHA-method)
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2. A list of all color scales is displayed.
3. Select the required scale.
4. Press OK to confirm.
5. The current result of the actual reading and all further
measurements will be displayed in the selected color scale.
DIN 6162 defines the Iodine color value as mg of iodine per 100 mL
of potassium iodide solution. Color matching with the Iodine color
determines the depth of color of clear liquids like solvents,
plasticisers, resins, oils and fatty acids, whose color is similar to
that of a solution of iodine and potassium iodide of the same
thickness.
For iodine color values of less than or approximately 1, the
determination of the Hazen value according to DIN-ISO 6271 is to
be preferred. Sampling and preparation are described in section
on page 29.The Iodine value can be accurately determined using
an 11 mm round glass cuvette/sample cell.
The Hazen color value (ISO 6271, also known as "AHPA-method "
or Platinum-Cobalt Scale) is defined as mg of platinum per 1 litre of
solution. The Hazen parent solution is composed of 1.246 g of
potassium hexachloroplatinate (IV) and 1.00 g of cobalt(II)chloride
dissolved in 100 ml of hydrochloric acid and filled up to 1000 ml with
distilled water.
The Hazen-color scale is used to evaluate the colors of nearly
water-clear products. It has narrower gradations in the light yellow
range than the Iodine scale and extends to water-clear color casts.
Note: Samples with Hazen values between 50 and 1000 can be measured
with sufficient accuracy in 10 mm square and 11 mm round
5.4