title: Slow-injection ultrasound-assisted emulsiﬁcation-microextraction for determination of phthalate esters in water.
abstract: A type of ultrasound-assisted emulsiﬁcation-microextraction (USAEME) was applied for the extraction and determination of four phthalate esters (e.g., dimethyl phthalate, diethyl phthalate, dibutyl phthalate and benzyl butyl phthalate) in aqueous samples prior to quantiﬁcation using HPLC-UV. The simultaneous injection of the extraction solvent and ultrasonication of the mixture results in an efficient extraction with the extractant well-dispersed in the sample. The parameters affecting the experimental results were analyzed and optimized through the design of the experiment. Using a central composite face-centered design, the results of 28 experimental data points were analyzed and validated. An optimal set of operating conditions was obtained using 40 μL of 1,1,2,2-tetrachloroethane and 1% NaCl subjected to 2.0 min of ultrasonication under natural pH. Under optimized conditions, the extractions resulted in analyte recoveries of 75-87% and high enrichment factors of 356-415. The calibration curves were linear, and the correlation coefficients ranged from 0.9992 to 0.9997 at concentrations of 5 to 300 μg L(-1). The RSDs (n = 5) were 5.6-7.9%. The limits of detection for the four phthalate esters ranged from 0.26 to 1.46 μg L(-1).
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian, Beijing 100193, PR China.
authors.forename: Songqing
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian, Beijing 100193, PR China.
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian, Beijing 100193, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian, Beijing 100193, PR China.
authors.forename: Runhua
authors.initials: R
authors.lastname: Lu
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian, Beijing 100193, PR China.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian, Beijing 100193, PR China hxgao@cau.edu.cn.
authors.forename: Haixiang
authors.initials: H
authors.lastname: Gao