APHA Color: Measurement of liquid purity

Time: 2017-12-26

APHA Color: Measurement of liquid purity

Purity is an important term we often take for granted in our daily life, but it is essential in the food we eat, the drugs we drink and the drinking water. The purity of clear liquid in petroleum, chemical, plastics, textiles, medicine and many other industries have applications. Using the APHA Color Index for color measurement enables products from these different industries to be kept secure and consistent.

The APHA (American Public Health Association) color scale was developed using the Hazen color index. Created by chemist A. Hazen in the late 19th century, the APHA color scale was used as a way to interpret "white water" and measure wastewater using the yellowness gradients. The system is used to evaluate the purity of wastewater and to detect traces of organic or other unwanted impurities. Other industries are also quick to assess the purity of their products using APHA color scales, which Hazen's Platinum-Cobalt (PtCo) based measurement systems can use.

Clear liquid medication APHA color — **Clear liquid purity Measured using the APHA color scale is critical to ensuring product safety and consistency as well as many different industries**

Picture credit: Flickr user Nathan Forget

APHA color standard

Compared with the platinum-cobalt control solution, the APHA color measurement method measures the yellow hue in a liquid. Often referred to as platinum / cobalt color, APHA color or Hazen color scale, the system is one of the most common standards for liquid color measurement. These standards have been perfected by the ISO (International Organization for Standardization) and have established precise guidelines for industrial applications. These new standards rely on spectral absorption measurements to calibrate APHA color standards and rely on advanced spectrophotometers. ASTM (American Society for Testing and Materials) also relies on the APHA / Pt-Co / Hazen color scale for standardization and is also cited in many industrial applications.

Translucent liquid APHA color — **In order to meet the APHA color standard, you need to use a spectrophotometer for calibration, measuring the yellow color of the liquid compared with the reference solution of platinum and cobalt**

Photo credit: Flickr user MartinKozák

The original liquid color standard uses a visual comparison to reference APHA / Pt-Co / Hazen color-coded samples. These systems are primarily intended to "characterize instruments prior to measuring liquid product samples, or to verify instrument-to-vision correlations." The new technology relies on advanced spectrophotometers to create internal diagnostic criteria for instrument performance verification. The ability to use advanced spectrophotometry to validate these standards provides a diagnostic tool for measuring samples related to the APHA color scale to maintain the accuracy and consistency of these results.

APHA color measurement instrument

Visual analysis of clear liquid color measurements is very subjective, leaving high errors in the purity analysis. "The instrumental approach provides objective quantification of the APHA color scale and is far more accurate than visual methods, especially for near colorless samples." HunterLab is a leader in spherical instrumentation technology that accurately measures vision ASTM D1209 APHA / Pt-Co based on Instrument ASTM D5386 method for color calibration.

Clear water APHA color — **Sphere instrument technology accurately measures the purity of a clear liquid and maintains consistency with industry standards**

Picture credit: Flickr user Stefan Lins

Applications and standardization vary by industry, but as a leader in color technology, YX offers a wide variety of instruments specifically designed for personal use and needs. Our friendly staff is knowledgeable, and we value our clients and strive to develop relationships that meet the needs and requirements of the changing color measurement industry. Contact Wing Hin Learn how color measuring instruments can help you meet today's purity and quality standards.

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