title: Using water plug-assisted analyte focusing by micelle collapse in combination with microemulsion electrokinetic chromatography for analyzing phthalate esters.
abstract: Phthalate plasticizers are widely used in the plastics industry, but they have been detected in soft drinks, pharmaceuticals and food products. This study developed a method that uses water plug-assisted analyte focusing by micelle collapse and microemulsion electrokinetic chromatography (WPA-AFMC-MEEKC) for quantifying benzyl butyl phthalate (BBP), dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP), and diisodecyl phthalate (DIDP) in pediatric pharmaceuticals. The AFMC strategy was applied to improve the detection sensitivity, and a short water plug was introduced to assist micelle collapse in the micelle dilution zone for sample stacking. To carry neutral phthalates into the capillary through electrokinetic injection, sodium dodecyl sulfate (SDS) was added to the sample solution, and 8mM SDS was selected as the optimal concentration. The optimized background solution (BGS) contained 16.13mM phosphate buffer (pH=2.5), 150mM SDS, 0.75% n-octane (v/v), 5% 1-butanol (BuOH), 22.5% acetonitrile (ACN), and 15% isopropanol (IPA). Under the optimal separation conditions, four phthalates could be quantified within 20min with enhancement factors of 58, 200, 86 and 90 for DIDP, DEHP, BBP, and DBP, respectively, compared to the conventional MEEKC mode. The limits of detection were within the range of 0.047-0.010μgmL(-1). The accuracy of the method was within the range of 96-117%. The WPA-AFMC-MEEKC method was applied for the analysis of six pediatric pharmaceuticals, and the results demonstrated that the developed method is sensitive and accurate, allowing it to be used for quality control of pediatric pharmaceuticals.
authors.affiliation: School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Hsi-Chun
authors.initials: HC
authors.lastname: Chao
authors.affiliation: School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Hsiao-Wei
authors.initials: HW
authors.lastname: Liao
authors.affiliation: School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacy, National Taiwan University Hospital, Taiwan. Electronic address: kuoch@ntu.edu.tw.
authors.forename: Ching-Hua
authors.initials: CH
authors.lastname: Kuo
mesh_terms: D020001:1-Butanol / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods*; D020374:Chromatography, Micellar Electrokinetic Capillary; D004785:Environmental Pollutants / Q000032:analysis*; D004952:Esters / Q000032:analysis*; D057230:Limit of Detection; D008823:Micelles; D009795:Octanes / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000032:analysis*; D010795:Phthalic Acids / Q000737:chemistry; D010968:Plasticizers / Q000032:analysis*; D015203:Reproducibility of Results; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D004952:Esters; D008823:Micelles; D009795:Octanes; D004364:Pharmaceutical Preparations; D010795:Phthalic Acids; D010968:Plasticizers; D014867:Water; D012967:Sodium Dodecyl Sulfate; C032279:phthalic acid; D020001:1-Butanol; C026728:octane
keywords: MEEKC; Pediatric pharmaceuticals; Phthalates; WPA-AFMC