On_line Preconcentration for Sensitive Analysis of PAHs in Cosmetics by Reversed Microemulsion Electrokinetic Chromatography / 分析化学

ABSTRACT

A sensitive analytical method based on reversed microemulsion electrokinetic chromatography ( MEEKC) combined with on_line preconcentration technique was developed for the determination of polycyclic aromatic hydrocarbons ( PAHs ) in cosmetics. For six lipophilic PAHs analytes which are difficult to be separated under conventional conditions, three stacking techniques including large volume sample stacking ( LVSS) , dynamic pH junction and sweeping ( LVSS_DypH_sweep ) were combined to realize the efficient preconcentration and separation. Under the optimum conditions, including the microemulsion buffer with the composition of 2. 4%(w/w)SDS_0. 6% (w/w) octane_6. 6% (w/w)n_butyl alcohol_20 mmol/L NaH2PO4 ( pH 2 . 2 ) , HCB injection time of 20 s ( 16 kPa ) and sample injection time of 80 s ( 16 kPa ) , good enrichment effect was reached with the enrichment factors ranged from 25 to 80 , and the PAHs were analyzed successfully within 27 min. The developed method was used to analyze the PAHs in cosmetics. The recoveries ranged from 90 . 6% to 95 . 9%. The RSD values ( n=5 ) were less than 5 . 1%.