- 作者: --
- 作者服務機構: Department of Chemistry, Faculty of Science, Zanjan University, P.O. Box 45195-313, Zanjan, Iran
- 中文摘要: Solvent extraction of a mixture of PbII, MnII, FeIII, CoII, NiII and CdII in aqueous perchlorate medium by a phosphorylated hexahomotrioxacalix[3]arene (calix-3) in dichloromethane shows a significant selectivity towards lead ions. The ligand can also be incorporated into a membrane to provide a new lead ion-selective electrode (PbII-ISE). A plasticized PVC membrane containing 30% PVC, 53.5% ortho-nitrophenyloctylether (NPOE), 4.5% sodium tetraphenylborate (NaTPB) and 12% ionophore was directly coated on a graphite rod. This sensor gave a good Nernstian response of 29.7 ± 0.7 mV decade-1 over a concentration range of 1 ’ 10-8 - 1 ’ 10-4 M of lead ions, independent of pH in the range 3-7, with a detection limit of 0.4 ’ 10-8 M. The dynamic response time of the electrode to achieve a steady potential was very fast and found to be less than 7 s. The selectivity relative to Ag+, NH4+, Li+, Na+, K+, Ca2+, Sr2+, Ba2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Fe3+, La3+, Sm3+, Dy3+, Er3+, Y3+ and Th4+ was examined. The electrode exhibits adequate stability with good reproducibility (with a slope of 29.6 ± 1.5 mV for 8 weeks). The characteristics of the sensor are compared with those of a tetraphosphorylated calix[4]arene (calix-4) based PbII-ISE, reported recently. The electrode was successfully used as an indicator electrode for a potentiometric titration of a lead solution using a standard solution of EDTA. The applicability of the sensor for lead ion measurements in various synthetic samples was also investigated.
- 英文摘要: --
- 中文關鍵字: Phosphorylated calix[3]arene; Lead-selective electrode.
- 英文關鍵字: --