New lead (II) selective membrane potentiometric sensors based on chiral 2,6-bis-pyridinecarboximide derivatives

摘要

New membrane sensors with cylindrical configuration for leas (II) ions are described based on the use of three newly synthesized pyridine carboximide derivatives as neutral ionophores in plasticized PVC membranes.The sensore exhibit significantly enhanced response to wards lead(II) ions over the concentration range 4 x 10~6-1 x 10~-2 moll~-1 at pH 4.5-7 with a lower detedtion limit of 0.4-3.7 mug ml~-1 .The sensors display near-Nernstian slope of 26.0-33.1 mV per decade for Pb(II)ions Effects of plasticizers,lipophilic salts and various foreing common ions are tested.The sensors show long life span,good selectivity for Pb(II) over a wide variety of other metal ions long term stability high reproducbility and fast responseValidation of the method by measuring the lower detection limit range accuracy precision repeatability and between-day-variability reveals good perfomance characteristics of the proposed sensors The sensors are used for direct determination of lead in stack emissions of lead smelters assay of lead in rocks and monitoring of potentiometric atitation of Pb(II) with EDTA.The results obtained agree fairly well with data obtained by atomic absorption spectrometry.