Product category:
Titration equipment
News Release from: Metrohm UK | Subject: High Sense Surfactant Electrode
Edited by the Laboratorytalk Editorial
Team on 27 October 2003
Two-phase titration rendered obsolete
PVC membrane electrode has ionophore/plasticiser membrane composition optimised for the determination of ionic surfactants
The Metrohm High Sense Surfactant Electrode renders two-phase titration obsolete - no more need for toxic chloroform Surfactant analysis is extremely important the world over
This article was originally published on Laboratorytalk on 2 Jul 2008 at 8.00am (UK)
Related stories
Analysis of mercury in waters using voltammetry
Jonathan Bruce, Applications Manager for Metrohm UK, provides this comprehensive introduction to analysis of mercury in waters
On-line lactic acid analysis of dairy products
Determination of lactic acid in milk and associated dairy products is an extremely common laboratory application and has key product quality control use in a modern dairy
Surfactants are crucial constituents, particularly in cosmetics, detergents, cleansers and pharmaceuticals.
Whether in formulations or starting materials - the content should be determined as quickly, precisely and accurately as possible.
The hitherto usual two-phase titration employs chloroform, a solvent nowadays frowned upon.
Further, in several cases the titration endpoint can be detected only with difficulty and the titration cannot be automated.
The Metrohm High Sense Surfactant Electrode is a PVC membrane electrode whose membrane composition (ionophore/plasticiser) has been especially optimised for the determination of ionic surfactants.
The potential is formed by a specific interaction between the ion carrier incorporated in the PVC membrane and the analyte ions (surfactants) in the sample solution.
This interaction produces an electrical potential difference at the phase boundary sample solution/membrane that can be measured against a reference electrode.
The High Sense Surfactant Electrode has a working life of about one year or around 10,000 titrations, but should not come into contact with organic solvents such as acetone, tetrahydrofuran and chloroform.
The Titroprocessors or Titrinos are suitable for use as a titrator.
The choice of titrant is very important.
The lower the solubility of the compounds formed, ie, the longer the chains, the steeper and more pronounced the potential jumps.
The titrants are preferably used as 0.004mol/l solutions.
For anionic surfactants, the Tego trant A 100 titrant, available from Metrohm, has proved outstanding, whereas for cationic surfactants sodium dodecylsulphate (Merck 12533 or Fluka 71727) is normally used.
A large number of practical titrations have been performed in the Metrohm application laboratory.
These are described in Application Bulletin No 233 available free from Metrohm UK. Request a free brochure from Metrohm UK ...
• Metrohm UK: contact details and other news
• Email this article to a colleague
• Register for the free Laboratorytalk email newsletter
• Laboratorytalk Home Page
Search the Pro-Talk network of sites
