0086 18165740359Platinum-Cobalt Index ( APHA/Hazen/Pt-Co ) is a standardized index used to measure the color depth and clarity of liquids. It is widely used in various industries, such as petrochemicals, food, beverages, coatings, textiles, etc. Its principle is to determine the color of the sample by comparing it with a known platinum-cobalt solution. Platinum-Cobalt Index is essential for the quality control of liquid products, especially in industries that need to strictly monitor color consistency and transparency.
What is the Platinum-Cobalt Index?
The Platinum-Cobalt Index indicates the color depth of a liquid sample, and is usually expressed in Pt-Co units. A standard platinum-cobalt solution contains a certain proportion of platinum and cobalt ions, and its color and concentration are related to the pollutants, impurities and other components in the solution. The higher the Platinum-Cobalt Index, the darker the sample color, and vice versa. Generally speaking, the Platinum-Cobalt Index is mainly used in industries such as petroleum, chemicals, food, beverages and water treatment to ensure product quality, transparency and compliance with industry standards.
Measurement method of platinum-cobalt index
The Platinum Cobalt Index is usually measured by colorimetry, using specialized instruments in a laboratory environment for precise measurement. The process involves comparing a sample with a known standard solution to quantify its color depth. To ensure the accuracy of the test results, colorimeters and spectrophotometers are commonly used measurement tools.
The traditional method of measuring the platinum-cobalt index relies on manual visual comparison, which is not only highly subjective but also has large errors. With the development of science and technology, modern colorimeter and spectrophotometer have become the preferred equipment for measuring the platinum-cobalt index. Through these devices, users can obtain more accurate and reliable color data, thereby achieving automated and standardized quality control.
3nh Liquid Colorimeter TS4020
Platinum-Cobalt Index Measurement Procedure
1. Preparation of standard solution
Ingredients: Dissolve 1.246g potassium chloroplatinate (K₂PtCl₆) and 1.000g cobalt chloride hexahydrate (CoCl₂·6H₂O) in a solution containing 100mL of concentrated hydrochloric acid, and dilute to 1L with deionized water to obtain a 500-degree platinum-cobalt standard stock solution.
Gradient dilution: As needed, dilute the stock solution with deionized water to prepare a standard series of different chromaticities (such as 0, 10, 20, 50, 100, 200, 500 degrees) to ensure that the chromaticity range covers the samples to be tested.Distilled water ('water-white') is rated as APHA/Pt-Co 0. The reagent APHA/Pt-Co/Hazen stock solution carries a rating of 500 APHA/Pt-Co/Hazen.
2. Sample Pretreatment
Removal of suspended matter: If the water sample is turbid, it needs to be centrifuged or filtered through a 0.45μm filter membrane to eliminate the interference of suspended matter on color judgment.
pH adjustment: If the pH of the water sample deviates significantly from neutrality (such as strong acid/alkalinity), it needs to be adjusted to pH≈7 with dilute hydrochloric acid or sodium hydroxide to avoid the acid-base environment affecting the color.
3. Colorimetric Analysis
Visual colorimetry:
Pour the treated water sample and the standard series into Nessler colorimetric tubes to the same height.
Observe vertically against a white background (such as a colorimetric stand) and select the standard solution that is closest in color to the water sample. Its chromaticity is the platinum-cobalt index of the water sample.
Spectrophotometry:
The absorbance of the standard series and water samples was measured using a spectrophotometer or Liquid Colorimeter.
Draw a standard curve (chromaticity-absorbance) and obtain the corresponding chromaticity value through the absorbance of the water sample.
3nh Liquid Colorimeter TS4010 to measure platinum-cobalt index
4. Result processing
If the chromaticity of the water sample exceeds 500 degrees, it needs to be diluted before measurement, and the final result should be multiplied by the dilution factor.
Things to note
Scope of application: Applicable to water samples with yellow hue. If the color deviates from yellow (such as red or blue), other methods (such as dilution multiple method) need to be used instead.
Interference factors:
Turbid water samples must be pretreated, but it is necessary to ensure that the treatment process does not change the color of dissolved substances.
Strong oxidants or reducing agents may affect the valence state of platinum cobalt ions and need to be eliminated in advance.
Instrument calibration: Spectrophotometry requires regular instrument calibration to ensure the accuracy of the standard curve.
Environmental control: Visual color comparison should be carried out under uniform natural light or standard light source to avoid misjudgment of color difference caused by direct light.
3nh Benchtop Spectrophotometer - ideal platinum cobalt index measurement tool
As a leading supplier of color measurement instruments, 3nh provides high-precision, high-reliability colorimeter and spectrophotometer for various industries. These devices can not only meet general color measurement needs, but also the benchtop spectrophotometer can accurately measure the platinum cobalt index to ensure that the color of the product meets the standard requirements.
3nh benchtop Spectrophotometer
3nh's benchtop spectrophotometer uses advanced optical technology to provide accurate platinum cobalt index measurement results. Whether it is liquid, solid or coating, 3nh color measurement instruments can quickly and accurately obtain the color data of samples, helping companies achieve strict quality control. Our products also have the following advantages:
High-precision measurement : 3nh colorimeter uses advanced spectroscopic and colorimetric technology to provide extremely accurate platinum-cobalt index data to ensure the consistency of each measurement result.
Quick response : The measurement process is quick and easy, improving production efficiency.
User-friendly interface : Our equipment has an intuitive and easy-to-use operating interface, which allows users to easily get started without complex training.
Multi-function support : In addition to platinum-cobalt index measurement, 3nh's equipment also supports multiple functions such as color difference measurement and whiteness measurement, and is widely used in many industries such as coatings, plastics, food, and cosmetics.
In Conclusion
Use 3nh benchtop spectrophotometer and liquid colorimeter to measure platinum-cobalt index, improve measurement accuracy , and bring more efficient and accurate production management to enterprises.
If you are looking for a high-performance Pt-Co index measuring instrument, 3nh benchtop spectrophotometer or liquid colorimeter will be your ideal choice. We are committed to providing customers with the most advanced color measurement solutions to help your products stand out in the fierce market competition. Contact us now to learn more about our products and technical support to help you improve your quality management!
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