title: Simultaneous determination of six phthalate esters in bottled milks using ultrasound-assisted dispersive liquid-liquid microextraction coupled with gas chromatography.
abstract: A new method was developed for the simultaneous determination of six phthalate esters in bottled milks using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) followed by gas chromatography-flame ionization detection (GC-FID). 0.8 mL of methanol (dispersant) and 40 μL of CCl(4) (extractant) were injected into 8.0 mL of milk solution and then emulsified the mixture by ultrasound for 2.0 min to form the cloudy solution. Under the optimum condition, the enrichment factors of the analytes ranged from 220 to 270 fold and the recovery ranged from 93.2% to 105.7%. Good linearity was observed for all analytes in a range of 0.8-51 ngg(-1) with the correlation coefficient (r(2)) ≥ 0.9992. The limits of detection (LODs) based on signal to noise of 3 were 0.64-0.79 ngg(-1). The repeatability evaluated as intra-day and inter-day precision (relative standard deviation, RSD) were less than 4.0% (n=5). The presented UA-DLLME-GC-FID method was successfully applied to determine the six phthalate esters in different bottled milk products.
authors.affiliation: Key Laboratory of Pharmaceutical Quality Control of Hebei Province & College of Pharmacy, Hebei University, Baoding 071002, China. yanhy@hbu.edu.cn
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Yan
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Cheng
authors.forename: Baomi
authors.initials: B
authors.lastname: Liu
mesh_terms: D000818:Animals; D002251:Carbon Tetrachloride; D005591:Chemical Fractionation / Q000379:methods*; D002849:Chromatography, Gas / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008832:Microchemistry / Q000379:methods; D008892:Milk / Q000737:chemistry*; D009994:Osmolar Concentration; D010795:Phthalic Acids / Q000032:analysis* / Q000302:isolation & purification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014465:Ultrasonics / Q000379:methods
chemical_list: D010795:Phthalic Acids; D002251:Carbon Tetrachloride