743792.fig.001
Figure 1: The effect of pH on the absorbance of the system, conditions: sample volume 5.0 mL containing 1.0 ng mL−1 of Zn(II), dispersive solvent 1.0 mL ethanol, extraction solvent 100 μL CCl4 containing 1.0 × 10−6 mol L−1 of PPT, extraction time 10 min.