title: Application of a multivariate approach for analyte focusing by micelle collapse-micellar electrokinetic chromatography for analyzing sunscreen agents in cosmetics.
abstract: The operating parameters that affect the performance of the online preconcentration technique "analyte focusing by micelle collapse-MEKC (AFMC-MEKC)" were examined using a multivariate approach involving experimental design to determine the sunscreen agents in cosmetics. Compared to the single-variable approach, the advantage of the multivariate approach was that many factors could be investigated simultaneously to obtain the best separation condition. A fractional factorial design was used to identify the fewest significant factors in the central composite design (cCD). The cCD was adopted for evaluating the location of the minimum or maximum response in this study. The influences of the experimental variables on the response were investigated by applying a chromatographic exponential function. The optimized condition and the relationship between the experimental variables were acquired using the JMP software. The ANOVA analysis indicated that the Tris pH value, SDS concentration, and ethanol percentage influenced the separation quality and significantly contributed to the model. The optimized condition of the running buffer was 10 mM Tris buffer (pH 9.5) containing 60 mM SDS, 7 mM γ-CD, and 20% v/v ethanol. The sample was prepared in 100 mM Tris buffer (pH 9.0) containing 7.5 mM SDS and 20% v/v ethanol. The SDS concentration in the sample matrix was slightly greater than the CMC value that makes the micelle be easily collapsed and the analytes be accumulated in the capillary. In addition, sunscreen agents in cosmetics after 1000-fold dilution were successfully determined by AFMC-MEKC.
authors.affiliation: School of Pharmacy, College of Pharmacy, China Medical University, Taichung, Taiwan.
authors.forename: Yi-Hui
authors.initials: YH
authors.lastname: Lin
authors.affiliation: Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chi-Yu
authors.initials: CY
authors.lastname: Lu
authors.affiliation: Department of Chemistry, College of Science, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Shiuh-Jen
authors.initials: SJ
authors.lastname: Jiang
authors.affiliation: Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wen-Yao
authors.initials: WY
authors.lastname: Hsiao
authors.affiliation: Pharmaceutical Optimization Technology Division, Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan.
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Cheng
authors.affiliation: Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.|Department of Marine Biotechnology and Resources, College of Marine Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Yen-Ling
authors.initials: YL
authors.lastname: Chen
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003358:Cosmetics / Q000737:chemistry*; D008823:Micelles; D015999:Multivariate Analysis; D013473:Sunscreening Agents / Q000032:analysis* / Q000737:chemistry
chemical_list: D003358:Cosmetics; D008823:Micelles; D013473:Sunscreening Agents
keywords: Analyte focusing by micelle collapse-micellar electrokinetic chromatography; Central composite design; Fractional factorial design; Multivariate approach; Sunscreen agents