Determination of phthalate esters in edible oils by use of QuEChERS coupled with ionic-liquid-based dispersive liquid-liquid microextraction before high-performance liquid chromatography

Anal Bioanal Chem. 2014 Jul;406(18):4563-9. doi: 10.1007/s00216-014-7814-8. Epub 2014 May 11.

Abstract

A selective and low organic-solvent-consuming method of sample preparation combined with high-performance liquid chromatography with diode-array detection is introduced for analysis of phthalic acid esters in edible oils. Sample treatment involves initial liquid-liquid partitioning with acetonitrile, then QuEChERS cleanup by dispersive solid-phase extraction with primary secondary amine as sorbent. Preconcentration of the analytes is performed by ionic-liquid-based dispersive liquid-liquid microextraction, with the cleaned-up extract as disperser solvent and 1-hexyl-3-methylimidazolium hexafluorophosphate as extraction solvent. Under the optimized conditions, correlation coefficients (r) were 0.998-0.999 and standard errors (S y/x ) were 2.67-3.37 × 10(3) for calibration curves in the range 50-1000 ng g(-1). Detection limits, at a signal-to-noise ratio of 3, ranged from 6 to 9 ng g(-1). Intra-day and inter-day repeatability, expressed as relative standard deviation, were in the ranges 1.0-6.9 % and 2.4-9.4 %, respectively. Recovery varied between 84 % and 106 %. The developed method was successfully used for analysis of the analytes in 28 edible oils. The dibutyl phthalate content of four of the 28 samples (14 %) exceeded the specific migration limit established by domestic and international regulations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid / methods*
  • Dibutyl Phthalate / analysis
  • Endocrine Disruptors / analysis
  • Esters / analysis
  • Food Analysis / methods*
  • Food Contamination / analysis
  • Ionic Liquids / chemistry
  • Limit of Detection
  • Liquid Phase Microextraction / methods*
  • Phthalic Acids / analysis*
  • Plant Oils / analysis*
  • Reproducibility of Results
  • Signal-To-Noise Ratio
  • Water Pollutants, Chemical / analysis

Substances

  • Endocrine Disruptors
  • Esters
  • Ionic Liquids
  • Phthalic Acids
  • Plant Oils
  • Water Pollutants, Chemical
  • Dibutyl Phthalate
  • phthalic acid