APHA Color Determination - UV Vis Spectroscopy
APHA Color measurements of near-clear samples according to CIE
This application note investigates the spectroscopic method for the determination of CIE tristimulus color values of several near-clear samples. To find out more, please proceed to the download button below.
What is APHA Color?
The APHA color space, synonymous to Pt-Co and Hazen, quantifies the yellowness of near-clear substances, and therefore serves as a determination of purity and quality of products in industries such as pharmaceutical, water and chemical. A color can be defined by its tristimulus values, X,Y and Z, the measurement of which is the objective of this application note, specifically the method recommended by CIE. This is an abbreviation for Commission Internationale de l'éclairage, an international body established in 1931 who regulates color standards.
How is APHA Color measured?
This method is applicable to the measurement of clear, liquid samples, free of haze, and non-fluorescent, with light absorption characteristics similar to those of platinum-cobalt standard solutions. The color is measured as tristimulus values of the percentage transmittance of light by a sample using deionized water as a blank. Then these tristimulus values are automatically converted to the APHA color scale by the UV/VIS Excellence spectrophotometer using appropriate mathematical equations.
Spectrophotometers from METTLER TOLEDO have preinstalled color measurement methods, enabling efficient measurement of APHA color. LabX PC software can be used to customize and manage workflows as well as edit and create automatic methods. For more information about this application, proceed to download the page.
