“…The small volume of the surfactant-rich phase obtained from CPE permits the design of extraction schemes of simplicity, high efficiency, rapidness and environmental friendliness, compared with conventional liquid-liquid extraction using organic solvents [2][3][4]. The application of CPE as sample preparation method has been well-documented in the literature for a variety of instrumental methods, such as flame atomic absorption spectrometry (FAAS) [5,6], inductively coupled plasma optical emission spectrometry (ICP-OES) [7,8], inductively coupled plasma mass spectrometry (ICP-MS) [9,10], gas chromatography (GC) [11], high-performance liquid chromatography (HPLC) [12,13], capillary electrophoresis (CE) [14][15][16], and chemiluminescence (CL) [17]. Apart from analyte preconcentration, CPE can also effectively eliminate the matrix effect encountered in ultrasensitive detection schemes, for example, ICP-MS [18] and graphite furnace atomic absorption spectrometry (GF-AAS) [19,20].…”