Separation and Preconcentration of Cd(II), Cu(II), Ni(II), and Pb(II) in
Water and Food Samples Using Amberlite XAD-2 Functionalized with
3-(2-Nitrophenyl)-1H-1,2,4-triazole-5(4H)-thione and Determination
by Inductively Coupled PlasmaAtomic Emission Spectrometry