A new method for trace Zn(II) preconcentration and separation was described using microcrystalline phenolphthalein modified by crystal violet as an adsorbent coupled with the determination by spectrophotometry. Under certain conditions Zn(II) was completely separatable from Ni(II), Cd(II), Al(III), Ca(II), Mg(II), Co(II), Mn(II), Pb(II), Cu(II), Fe(III) and hardly affected by, , Br^－, Cl^－, I^－,. The adsorption capacity of microcrystalline phenolphthalein was found to be 25.8 mg/g for Zn(II). The preconcentration factor can reach 200, and the recovery of Zn(II) is in a range of 97.7%～102%. The relative standard deviation (RSD) is not beyond 2.7%. The proposed method has been applied to the preconcentration and determination of trace Zn(II) in water samples with satisfactory results.

Key words: Zn(II), microcrystalline phenolphthalein, crystal violet, separation and concentration