“…The application of various calixarene platforms as well as conjugation of calix with nanomaterials as sensors has become an emerging topic of interest [20][21][22][23][24][25][26][27][28][29][30][31]. The present work represents a rapid, sensitive, low cost and convenient assay for Pb(II) detection in water using calix [4]resorcinarene tetrahydrazide [32]. Furthermore, the selectivity of Pb(II) detection system is excellent when tested against a series of heavy metal ions, such as Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) in both aqueous solutions and mixtures of these ions.…”