Determination of chlorophenols in water using dispersive liquid–liquid microextraction coupled with water‐in‐oil microemulsion electrokinetic chromatography in normal stacking mode

Abstract

The current routes to couple dispersive liquid-liquid microextraction with capillary electrophoresis are the evaporation of water immiscible extractants and the back-extraction of analytes. In this study, a new methodology for this combination using water-in-oil microemulsion electrokinetic chromatography coupled with normal stacking mode on-line sample concentration was developed to analyze chlorophenols in water samples. The analytes were extracted with tributyl phosphate and the extractant dilution (3×) was directly injected into an electrophoresis buffer (7.7 cm) containing 5% sodium dodecyl sulfate, 78% 1-butanol, 2% 1-heptane, and 15% sodium acetate solution (pH 8.0). This proposed method is very simple and convenient compared to the conventional procedures. The key parameters affecting separation and concentration were systematically optimized. Under the optimized conditions, dispersive liquid-liquid microextraction contributed an enrichment factor of 45-50, and the overall sensitivity improvement was 312-418-fold. Limits of detection between 1.4 and 3.0 ng/mL and limits of quantification between 4.5 and 10.2 ng/mL were achieved. Acceptable repeatability lower than 3.0% for migration time and 9.0% for peak areas were obtained. The developed method was successfully applied for analysis of the chlorophenols in real water samples.

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

“…Analytical performance of the developed DLLME‐CE was compared with other reported HPLC and GC methods for determination of CPs. As shown in Supporting Information Table 2, our method presents lower LODs (0.27–0.66 μg/L) for five CPs, in comparison with that reported MIPs‐SPE (0.57–1.08 μg/L) , CPE‐based HPLC (3.00–5.00 μg/L) , and DLLME‐MEEKC (1.40–3.00) methods . The LOQs of our study (1.01–2.43) are lower than that of DLLME‐MEEKC (4.50–10.20) .…”

“…As shown in Supporting Information Table 2, our method presents lower LODs (0.27–0.66 μg/L) for five CPs, in comparison with that reported MIPs‐SPE (0.57–1.08 μg/L) , CPE‐based HPLC (3.00–5.00 μg/L) , and DLLME‐MEEKC (1.40–3.00) methods . The LOQs of our study (1.01–2.43) are lower than that of DLLME‐MEEKC (4.50–10.20) . Although our LODs and LOQs are higher than that of MIPs‐DSPE and MIPs‐SPE methods, they require synthetic materials and thereby the processes are complicated and time/reagents‐consuming .…”

“…Various pretreatment and preconcentration procedures for CPs have been utilized, mainly including SPE , solid‐phase microextraction (SPME) , cloud point extraction (CPE) , liquid–liquid–liquid microextraction , and hollow fiber supported liquid–liquid–liquid membrane microextraction , dispersive liquid–liquid microextraction (DLLME) . In DLLME, the amount of extractant used is small, and the contact area between the extractant and the sample solution is maximized by the dispersant, so high enrichment factors (EFs) can be obtained.…”

Dispersive liquid‐liquid microextraction coupled with pressure‐assisted electrokinetic injection for simultaneous enrichment of seven phenolic compounds in water samples followed by determination using capillary electrophoresis

“…Considering their low concentration presented in complicated matrices, a number of pretreatment approaches have been developed to concentrate phenolic compounds, such as hollow fiber supported liquid‐liquid liquid membrane microextraction , SPE , dispersive solid phase extraction , SPME , dispersive liquid‐liquid microextraction (DLLME) and cloud point extraction . Moreover, various detection technologies have been applied for analysis of phenolic compounds including HPLC , CE , and GC coupled with UV, fluorescence, and MS detectors.…”

Determination of hexachlorophene in cosmetics by capillary electrophoresis compared with high performance liquid chromatography

“…CE methods especially capillary zone electrophoresis (CZE) have found their place in modern separation science as versatile and efficient techniques for the analysis of a wide range of analytes in a variety of sample matrices, such as the analytes of organic compound [22], inorganic ions [23,24], proteins [25], and vitamins [26], in a series of samples. CE based methods have been described in literatures for the quantification of chlorophenols in some matrices [27][28][29]. However, only one research has been reported regarding the determination of HCP in water samples by CE with electrochemical detection [30].…”