A novel 4-phenyl amino thiourea derivative designed for real-time ratiometric-colorimetric detection of toxic Pb~(2+)

摘要

The objective of this study was to develop a ratiometric and colorimetric organic sensor for Pb2+ detection in environmental samples. A new probe 4-phenyl amino thiourea (PAT) was designed and synthesized using hydrazine hydrate and phenyl isothiocyanate as raw materials. After its structure was characterized and confirmed, its UV-vis spectral property was investigated in detail. PAT possesses a specifically real-time, ratiometric and colorimetric response to Pb2+ in dimethyl formamide (DMF)/H2O (v/v = 9:1, pH = 7.0) within 18.0s. There was little interference in the presence of some other common metal ions, such as Fe3+, Cd2+, Zn2+, Mg2+, Cr3+, Ca2+, Ba2+, Sn2+, Na+, Mn2+, Hg2+, and Pb2+. Under the optimized conditions (DMF/H2O with v/v of 9:1, c(PAT) = 1.0x 10(-3) molboldL/bold-1, pH = 7.0), the present sensor PAT was successfully applied for Pb2+ determination in environmental water samples with satisfied recoveries (83.0%-106.0%) and analytical precision (7.2%). The recognition mechanism was confirmed to form a stable 1:1 six-member ring complex between the target dye and Pb2+ with a coordination constant of 4.96x 10(4).