Comparison of aromatic and alkyl micelles for the electrokinetic determination of phthalates in virgin olive oil

Abstract

Two electrokinetic methods for the separation of phthalates are proposed. One uses 25 mM sodium borate and 50 mM sodium taurodeoxycholate adjusted to pH 2.8, and the other uses 15 mM ammonium tetraborate, 100 mM SDS, 0.25% w:v hydroxypropylmethyl cellulose (HPMC) and 5% v:v methanol (MeoH) adjusted to pH 9. The BGE containing SDS micelles as the pseudo-stationary phase provided better analytical figures of merit, particularly as regards LOD (0.4-1.4 mg/L) and precision (1.1-6.5%). Adding MeoH and HPMC to the BGE proved essential in order to obtain narrow and symmetric peaks. The proposed method was successfully used to determine phthalates in virgin olive oil. Recoveries from spiked samples ranged from 96 to 106%. The precision obtained in the analysis of real samples, as RSD, was better than 6.8%.