Dispersive liquid-liquid microextraction of five chlorophenols in water samples followed by determination using capillary electrophoresis

Abstract

Dispersive liquid-liquid microextraction (DLLME) coupled with CE was developed for simultaneous determination of five types of chlorophenols (CPs), namely 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,6-dichlorophenol (2,6-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) in water samples. Several parameters affecting DLLME and CE conditions were systematically investigated. Under the optimized DLLME-CE conditions, the five CPs were separated completely within 7.5 min and good enrichment factors were obtained of 40, 193, 102, 15, and 107 for 4-CP, 2,4,6-TCP, 2,4-DCP, 2-CP, and 2,6-DCP, respectively. Good linearity was attained in the range of 1-200 μg/L for 2,4,6-TCP, 2,4-DCP, 2-300 μg/L for 4-CP and 2-CP, and 1-300 μg/L for 2,6-DCP, with correlation coefficients (r) over 0.99. The LOD (S/N = 3) and the LOQ (S/N = 10) were 0.31-0.75 μg/L and 1.01-2.43 μg/L, respectively. Recoveries ranging from 60.85 to 112.36% were obtained with tap, lake, and river water spiked at three concentration levels and the RSDs (for n = 3) were 1.31-11.38%. With the characteristics of simplicity, cost-saving, and environmental friendliness, the developed DLLME-CE method proved to be potentially applicable for the rapid, sensitive, and simultaneous determination of trace CPs in complicated water samples.

Keywords: Capillary electrophoresis; Chlorophenols; Dispersive liquid-liquid microextraction; Water samples.