Titrations
Titration is a common laboratory method of quantitative/chemical analysis which can be used to determine the concentration of a known reactant by the neutralization of analyte in solution with a calibrated reference solution. Titrations are commonly performed with either a colorimetric or potentiometric endpoint. In colorimetric titrations, an indicator compound is added which changes appearance when the endpoint is reached. For example in chloride titrations, an indicator is added which generates a red precipitate when the chloride is consumed.
In potentiometric titration, an electrode is used, and the electrode potential is plotted against the volume of titrant added. The endpoint is indicated by a rapid change in electrode potential over a small volume range. If a pH electrode is used, potentiometric titration can replace many colorimetric titration techniques, and is especially well suited for strongly colored samples. Other electrode types can be used for other other determinations. For example, a silver billet electrode can be used to titrate chloride ions in isocyanate samples.
Applications:
- Determination of acid/base content
- Determination of free acid groups/acid number for polymers
- Analysis of other compounds, such as chloride, bromide and mercaptans
- Moisture determination in solid plastic resins and in solvents.
- Contamination analysis
- Deformulation analysis
- Water quality analysis
- Chloride in isocyanates
- Acid-neutralization
- Amine endgroups in nylon
- Alcohol endgroups in polymers
- Neutralization of strong acid samples
- Hydroxyl content
- Acid endgroups of PLA