ALTANA LCM IV - Manual (Page 65)

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Standard programs
5.5.7.9 Determination of the Acid wash color
ASTM D848 - 09 is the standard test method for the acid wash
color in the "aromatic hydrocarbon" industry. The test procedure
covers the determination of the acid wash color for benzene,
toluene, xylene, refined solvents such as naphtha and similar
aromatic hydrocarbons. The color scale was developed for
detecting impurities in industrial aromatic hydrocarbons. Sulfur
contamination causes the material to discolor, for example.
5.5.7.10 Determination of the ICUMSA color index
The ICUMSA (International Commission for Uniform Methods of
Sugar Analysis) color index is a photometric method for color
correction of filtered sugar solutions. The test method is based on
the transmittance of the solution with a known concentration (Brix
value) at a wavelength of 420 nm.