Platinum-Cobalt color number

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The platinum-cobalt color number ( Pt / Co for short ), also APHA-Hazen color number after its inventor Allen Hazen , was developed in 1892 for the investigation of waste water. The samples are compared colorimetrically in standardized vessels against an acidic solution of potassium hexachloroplatinate (IV) and cobalt (II) chloride , which are assigned a color number between 0 and 500 (mg / l) according to their platinum content. The method is specific for yellowish coloring.

Norms

The procedure is described in detail in the following international and national standards:

  • ASTM D 1209 (2005): Standard Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)
  • BS 5339 (1976): Measurement of Color on Hazen Units (Platinum-Cobalt Scale)
  • ISO 2211 (1973): Liquid chemical products; Color measurement in Hazen units (platinum-cobalt scale)
  • DIN EN ISO 6271 (2005): Determination of the color of clear liquids according to the platinum-cobalt scale

Individual evidence

  1. ↑ Allen Hazen: The Measurement of the Colors of Natural Waters. In: Journal of the American Chemical Society . 1896, 18 (3), pp. 264-275, doi : 10.1021 / ja02089a012 .