Analytical Performance Characteristics of the Separation of Fluoride in Toothpaste by Capillary Zone Electrophoresis

Abstract

The analytical performance characteristics of the separation by CZE of fluoride in toothpaste using a chromate-based electrolyte is discussed. Good precisions (n = 5) were recorded for absolute migration time (1.7% RSD), peak area (0.8% RSD) and peak height (0.4% RSD). Fluoride was separated in under 4 min without matrix interference or co-migration with phosphate (resolution ca. 8). The peak area calibration curve was linear between 5–120 µg ml ^{- 1} of fluoride and using this curve, one toothpaste sample was determined to have about 12 µg ml ^{- 1} (≈0.1% m/m undried basis) of fluoride. The limit of detection was 0.5 µg ml ^{- 1} (3 × baseline noise) and the mean recovery was 106% (n = 10).