Determination of polyhexamethylene biguanide hydrochloride using photometric colloidal titration with crystal violet

Takashi Masadome1, Takaaki Miyanishi, Keita Watanabe

  • 1Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology, Toyosu, Koto, Tokyo 135-8548, Japan. masadome@sic.shibaura-it.ac.jp

Related Concept Videos

Precipitation Titration: Endpoint Detection Methods01:19

Precipitation Titration: Endpoint Detection Methods

In argentometric precipitation titrations, endpoints can be detected visually by the Mohr, Volhard, and Fajans methods. In the Mohr method, adding a soluble chromate indicator gives an initial yellow color to the analyte solution. As the titrant is added, the first excess of silver ions forms a red silver chromate precipitate, marking the endpoint. The solution pH should be maintained at about 8 by adding solid CaCO3.
In the Volhard method, a standard excess of AgNO3 is first added to the...
Complexometric Titration: Overview00:39

Complexometric Titration: Overview

Complexometric titration involves the formation of a complex by reacting a metal ion with one or more ligands. A visual indicator often detects the end point of a complexometric titration. It is added to the metal solution before the titration, forming a stable metal–indicator complex and imparting color to the solution. As the titration approaches the equivalence point, the excess of the added ligand displaces the indicator from the metal–indicator complex, releasing the free indicator. The...
Precipitation Titration: Overview01:26

Precipitation Titration: Overview

Precipitation titration involves the reaction of a titrant and an analyte to generate an insoluble precipitate. While precipitation titration uses various precipitating agents, silver nitrate is the most common precipitating reagent; titrations involving Ag+ are called argentometric titrations. Usually, the endpoint in a precipitation titration can be detected by visual indicators.
A precipitation titration curve demonstrates the change in concentration of the titrant or analyte upon adding the...
Effects of EDTA on End-Point Detection Methods01:18

Effects of EDTA on End-Point Detection Methods

Different methods, such as visual observance of metal-ion indicators, spectroscopic techniques, and potentiometric methods, can determine the endpoint of an EDTA titration.
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
Titration of Polyprotic Base with a Strong Acid01:18

Titration of Polyprotic Base with a Strong Acid

The titration of a polyprotic base such as sodium carbonate with a strong acid such as hydrochloric acid results in two equivalence points on the titration curve. At the first equivalence point, the carbonate ions in the base are completely converted to bicarbonate ions. The second equivalence point corresponds to the complete conversion of bicarbonate ions to carbonic acid, which dissociates into carbon dioxide and water. The region before the first equivalence point corresponds to the...