Halogen-free ionic liquid as an additive in zinc(II)-selective electrode: Surface analyses as correlated to the membrane activity

• Published in: Talanta (Oxford) Vol. 94; pp. 184 - 188
• Main Authors: Al-Asousi, Maryam F., Shoukry, Adel F., Bu-Olayan, Abdul Hadi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30-05-2012; Elsevier
• Subjects: Additives; Analytical chemistry; Atomic force microscopy; Chemistry; Crown Ethers - chemistry; Diethylhexyl Phthalate - chemistry; Electrochemical methods; Electrodes; Exact sciences and technology; General, instrumentation; Halogen-free ionic liquid; Hydrogen-Ion Concentration; Ion-scattering spectroscopy; Ionic liquids; Ionic Liquids - chemistry; Kinetics; Membranes; Membranes, Artificial; Microscopy, Atomic Force; Photoelectron Spectroscopy; Plasticizers; Plasticizers - chemistry; Polyvinyl Chloride - chemistry; Polyvinyl chlorides; Potentiometry - methods; Selectivity; Solutions; Spectrometric and optical methods; Sulfonates; Surface Properties; Tetraphenylborate - analogs & derivatives; Tetraphenylborate - chemistry; Water; X-ray photoelectron spectroscopy; Zinc - analysis; Zn(II) ion-selective electrode; Ion-scattering spectroscopy; Halogen-free ionic liquid; Atomic force microscopy; Zn(II) ion-selective electrode; X-ray photoelectron spectroscopy; Water; Crown compound; Selectivity; Surface analysis; Ionic liquid; Sulfonate; Additive; Halogen; Ion spectrometry; Membrane; Photoelectron spectrometry; Polyvinyl chloride; Membrane electrode; Zinc II; Use; TOA; X ray spectrometry; Lon-scattering spectroscopy; Chemical sensor; Ion selective electrode; Plasticizer; Phase equilibrium; Potassium; Borates
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2012.03.016

► A halogen-free ionic liquid, as an additive for Zn(II) electrode, increased the selectivity of the sensor. ► X-ray photoelectron- and ion scattering spectroscopy proved ion transport through the membrane. ► Atomic force microscopy explored the morphological changes of the membrane surface when conditioned.
Two conventional Zn(II) polyvinyl chloride (PVC) membrane electrodes have been prepared and characterized. They were based on dibenzo-24-crown-8 (DBC) as a neutral carrier, dioctyl phthalate (DOP) as a plasticizer, and potassium tetrakis (p-chlorophenyl) borate, KTpClPB or the halogen-free ionic liquid, tetraoctylammonium dodecylbenzene sulfonate [TOA][DBS] as an additive. The use of ionic liquid has been found to enhance the selectivity of the sensor. For each electrode, the surfaces of two membranes were investigated using X-ray photoelectron, ion-scattering spectroscopy and atomic force microscopy. One of the two membranes was conditioned by soaking it for 24h in a 1.0×10−3M Zn(NO3)2 solution and the second was soaked in bi-distilled water for the same interval (24h). Comparing the two surfaces indicated the following: (a) the high selectivity in case of using [TOA][DBS] as an additive is due to the extra mediation caused by the ionic liquid and (b) the working mechanism of the electrode is based on phase equilibrium at the surface of the membrane associated with ion transport through the bulk of the membrane.