Under the optimized
extraction conditions, the method exhibited good sensitivity with the limits of detection (LODs) at
5.5 μg L1 and 10.0 μg L1 for 4-nitrophenol and 2-naphthol, respectively. Good linearity over the
concentration ranges of 24–384 μg L1 for 4-nitrophenol and 28–336 μg L1 for 2-naphthol was
obtained with correlation coefficients of 0.9998 and 0.9961, respectively. The proposed method can
directly extract acidic compound from environmental sample or even more complex sample matrix
without any pH adjustment procedure.