Titration

ASTM D6869

Titration is a chemical analysis method used to determine the exact concentration of a substance within a given sample by measuring its reaction to a titrant, or controlled substance added to the sample in precise quantities in a laboratory environment.

Titration may be used to quantify a wide variety of substances, such as metals, chemicals, ash, and carbon black. It is also commonly used to determine water or moisture content. Because it is such a versatile method, many industries leverage titration chemistry to assess concentration, purity, and other properties. For example:

  • Food and beverage companies may use titration to measure the acidity of fruit juice or the salt quantity in a food product.
  • A pharmaceutical company may use titration chemistry to adjust dosages by measuring possible side effects, quantify the concentration of preservatives or fillers, test the purity of a drug product or dose, and assess the water content in order to determine the storage longevity or shelf life of a drug product.
  • A materials company may use titration to determine the pH or moisture content of latex, rubber, plastic, or other materials.

 

Titration testing can be used for quality assurance, research and development (R&D), and regulatory purposes. Some quality standards or industry specifications prohibit concentrations of certain substances over a certain threshold, such as a certain number of parts per million. Titration allows developers and manufacturers to accurately quantify those regulated substances and, if necessary, make adjustments.

Titration Testing Summary

The titration testing process begins with a prepared sample for testing. As mentioned, this may be a food product, a drug project, a material sample, or some other substance. A “titrant” is then introduced to the sample.

A titrant contains a chemical that is known to react with the sample substance. The specific titrant being used will vary depending on the material or substance undergoing titration testing.

A specified quantity of the titrant is added to the sample, at which point a chemical reaction can be observed. This reaction is often a color change, though other indicators may be used.

More and more titrant may be added until all of the substance has reacted. The exact quantity of titrant must be accurately recorded, since the quantity of the titrant is used to calculate the concentration of the substance being measured.

 

ASTM D6869 Testing Process

One important application for titration testing is determining the volume of moisture in a material, such as a rubber or plastic compound. ASTM D6869 is a standard test method designed specifically for plastics and uses the Karl Fischer reaction for coulometric and volumetric determination of moisture. The method can measure moisture content ranging from concentrations of 0.005% to 100%. The titrant used in ASTM D6869 is iodine.

ASTM D6869 is often used when assessing the processability of plastics, since moisture content can affect both processability and physical properties. For example, excess moisture can cause splay, bubbling, or other surface imperfections, whereas too little moisture can cause polymerization at high temperatures.

ASTM D6869 is equivalent to Method B of ISO 15512: Plastics — Determination of water content.

 

Material Testing From ACE

The analytical chemistry team at ACE Laboratories has a comprehensive and practical understanding of titration testing and other material properties testing methods for quantifying the concentration of moisture, acid, and other substances within a given compound. We can help you understand the exact composition of your product or material, the implications of substance quantities, and your options for next steps, as necessary.

ACE Laboratories can conduct testing to industry standards for the sake of regulatory compliance or develop a custom testing plan to address a specific problem or question.

To learn more about titration testing from ACE Laboratories, talk to a member of our team >

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