Determination of parabens in human milk and other food samples by capillary electrophoresis after dispersive liquid–liquid microextraction with back-extraction

•DLLME was coupled to CE to determine four parabens in human milk and food samples.•DLLME–CE reduces organic solvents and extraction time significantly.•DLLME–CE requires minimum variation in the extraction procedure for food samples.•Parabens were not detected in the analysed food samples.•Low LODs, good recoveries and interference-free electropherograms were obtained.

Dispersive liquid–liquid microextraction (DLLME) with back-extraction was used prior to capillary electrophoresis (CE) for the extraction of four parabens. Optimum extraction conditions were: 200 μL chloroform (extraction solvent), 1.0 mL acetonitrile (disperser solvent) and 1 min extraction time. Back-extraction of parabens from chloroform into a 50 mM sodium hydroxide solution within 10 s facilitated their direct injection into CE. The analytes were separated at 12 °C and 25 kV with a background electrolyte of 25 mM borate buffer containing 5.0% (v/v) acetonitrile. Enrichment factors were in the range of 4.3–10.7 and limits of detection ranged from 0.1 to 0.2 μg mL−1. Calibration graphs showed good linearity with coefficients of determination (R2) higher than 0.9957 and relative standard deviations (%RSDs) lower than 3.5%. DLLME–CE was demonstrated to be a simple and rapid method for the determination of parabens in human milk and food with relative recoveries in the range of 86.7–103.3%.