Skip to Content
Merck
  • New tetradecyltrimethylammonium-selective electrodes: surface composition and topography as correlated with electrode's life span.

New tetradecyltrimethylammonium-selective electrodes: surface composition and topography as correlated with electrode's life span.

Talanta (2012-03-01)
Hayat M Marafie, Tahani F Al-Shammari, Adel F Shoukry
ABSTRACT

Two conventional plastic membrane electrodes that are selective for the tetradecyltrimethylammonium cation (TTA) have been prepared. The ion exchangers of these sensors were the ion associate, TTA-PT, and the ion aggregate, TTA-PSS, where PT and PSS are phosphotungstate and polystyrene sulfonate, respectively. The following performance characteristics of the TTA-PT- and TTA-PSS-containing electrodes were found: conditioning time of 30 and 20 min; potential response of 58.2 and 61.1 mV/TTA concentration decade; rectilinear concentration ranges of 2.0 × 10(-5)-5.0 × 10(-2) and 1.5 × 10(-5)-7.9 × 10(-2) mol L(-1); average working pH ranges of 4.0-10.5 and 3.8-10.7; life spans of 20 and 28 weeks, and isothermal temperature coefficients of 4.44 × 10(-4) and 6.10 × 10(-4)V/°C, respectively. Both electrodes exhibited high selectivity for TTA with an increasing number of inorganic and quaternary ammonium surfactant cations. These electrodes have been successfully applied to assay an antiseptic formulation containing TTA. Surface analyses using electron microscopy and X-ray photoelectron spectroscopy were used to determine the cause of the limited life span of plastic membrane electrodes.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Trimethyl-tetradecylammonium chloride, ≥98.0% (AT)
Supelco
Myristyltrimethylammonium bromide, suitable for ion pair chromatography, LiChropur, ≥99.0% (AT)
Sigma-Aldrich
Myristyltrimethylammonium bromide, ≥99%
Sigma-Aldrich
Myristyltrimethylammonium bromide, 98% (AT)