title: 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.
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.
authors.affiliation: College of Science, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi, 712100, China.
authors.forename: Qilong
authors.initials: Q
authors.lastname: Xie
authors.forename: Shuhui
authors.initials: S
authors.lastname: Liu
authors.forename: Yingying
authors.initials: Y
authors.lastname: Fan
authors.forename: Jianzhi
authors.initials: J
authors.lastname: Sun
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Zhang
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003993:Dibutyl Phthalate / Q000032:analysis; D052244:Endocrine Disruptors / Q000032:analysis; D004952:Esters / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D052578:Ionic Liquids / Q000737:chemistry; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D010795:Phthalic Acids / Q000032:analysis*; D010938:Plant Oils / Q000032:analysis*; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D052244:Endocrine Disruptors; D004952:Esters; D052578:Ionic Liquids; D010795:Phthalic Acids; D010938:Plant Oils; D014874:Water Pollutants, Chemical; D003993:Dibutyl Phthalate; C032279:phthalic acid