A Novel Highly Selective and Sensitive Nano-Molar Cu(I), Cu(II) Modified Carbon Paste Sensors Based on Thiosemicarbazide and Acetaldehydethiosemicarbazone

A novel highly selective and sensitive nano Molar Concentration Cu(I) and Cu(II) ion-chemically modified carbon based electrode (CMCPE) based on the metal complexes, [Cu(HTS)(TS)(ac)2].(C2H5OH) or [Cu(ATS)2(ac)(H2O)].(H2O) dissolved in tricresyl phosphate (TCP) as pasting liquid were prepared. The modified electrodes showed Nernstian slopes of 60.5 mV and 29.5±1 mV per decade for Cu(I) or Cu(II) ions over the concentration range 0.012 nM up to 1.0×10 −2 M and 0.016 nM up to 7.9×10 −3 M and a detection limit of 0.398 and 0.630 nM respectively. The sensor has a relatively fast response time of < 10 s and it can be used in the pH range of 3.8–8.0. The selectivity coefficients for mono-, di-, and trivalent cations indicate the good selectivity of sensor for Cu (I) and Cu (II) ions over a large number of interfering cations. As a result the proposed electrodes were applied to Cu (I) and Cu (II) ions determination in mixture soutions, waste water samples. The materials [Cu(TS)(HTS)(ac)2].(C2H5OH) and [Cu(ATS)2(ac)(H2O)].(H2O), were isolated by the anodic dissolution of Copper metal in an anhydrous acetone solution of the ligands where HTS is thiosemicarbazide, HATS is acetaldehydethiosemicarbazone ligand and ac = acetone. Elemental analysis, magnetic susceptibility measurements, molar conductance, thermal analysis and spectroscopic techniques has been used for characterization and elucidation for the structure the isolated materials. [Cu(TS)(HTS)(ac)2].(C2H5OH) shows diamagnetic moment which may be arising from anodic dissolution of Cu(I) during the electrolysis of Copper metal during electrochemical preparation.