Özet:

Dispersive liquid--liquid microextraction followed by a back-extraction step was combined with HPLC-DAD for the determination of four parabens (i.e. methyl-, ethyl-, propyl-, and butylparaben). Optimum extraction conditions were found as follows: 225 $\mu $L of chloroform, 0.75 mL of ethanol, 7.5 mL of aqueous solution and within an extraction time of 15 s. Back-extraction into 100 $\mu $L of 50 mM sodium hydroxide solution within 20 s resulted in a reversed-phase HPLC-compatible extract. The analytes were separated at 20 $^{\circ}$C using methanol (A) and water (B), 40:60 (A:B, v/v) as the mobile phase, a flow rate of 1.0 mL min$^{-1}$ and an injection volume of 20 $\mu $L. DAD was set at 258 nm to monitor the analytes. Limits of detection and quantitation were as low as 0.1 and 0.3 $\mu $g mL$^{-1}$, respectively. Coefficients of determination (R$^{2})$ were higher than 0.9950 and percentage relative recoveries were found in the range of 86.5-114.5% for the four parabens from pharmaceuticals and personal care products.

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