Perspectives of Carbon Paste Electrodes in Stripping Potentiometry

Abstract

Experimental ApparatusAn AUTOLAB PGSTAT 10 system equipped with ECD-MODUL and controlled by GPES software (Ecochemie, Utrecht, Holland) was used in combination with an electrode stand (Metrohm, Switzerland) adapted for measurements with CPEs. Besides a CPE (see below), the electrode cell involved also a Pt-wire auxiliary and an Ag/AgCl reference electrode (saturated solution of KCl; Metrohm, Switzerland). Stirring was performed with a Teflon-coated bar at approx. 100 rpm using a magnetic stirrer (Model E 405, Metrohm). Chemicals and reagentsAll chemicals and standard solutions used were of analytical reagent grade and were purchased from Laboratorijske Kemikalije (Slovenia), Kemika Zagreb (Croatia), and Merck. Stock solutions for the preparation of the supporting electrolytes were made 1 mol/L in concentration; standard test solutions used were 0.01 M. The testing of various types of carbon paste electrodes (CPEs) for their use in stripping potentiometry was carried out by means of specially proposed procedures and by using various model analyte systems. CPEs containing three different pasting liquids (paraffin oil, silicone oil, tricresyl phosphate) were tested as supports for mercury-and gold films, and as substrates for electrolytic, adsorptive, ion-pair forming, and extractive accumulation. Test measurements in organic solvent-containing media and studies of some irreversible electrochemical reactions were performed as well. Individual examples to be studied allowed one to formulate and outline some perspectives of CPEs in potentiometric stripping analysis and related constant current stripping analysis.

Modification of Carbon Paste Electrode With Crown Ether (Dibenzo-18-Crown-6) for Ascorbic Acid Analysis Using Differential Pulse Voltammetry Method

“…Grafit digunakan sebagai bahan elektroda karena mempunyai daya hantar listrik yang baik, bersifat inert, dan memiliki rentang potensial yang lebar. Parafin cair digunakan sebagai pengikat karena dalam pengukuran tidak ikut bereaksi (inert) dan stabil dalam campuran (Svancara et al, 2002). Penggunaan eter mahkota yang sebelumnya hanya digunakan sebagai modifier dalam analisis logam alkalidan ion logam transisi, diharapkan dapat digunakan sebagai modifier untuk analisis senyawa organik seperti asam askorbat.…”

Carbon paste electrodes in the new millennium

“…This was shown already in the first years of a new millennium; e.g., a former procedure elaborated for the determination of thallium [333] could be adapted for gold (as tetrachloroaurate [99,331]), or iodide [101,331], and the perspectives of stripping potentiometry with CPEs, focused on the role of pasting liquid, were thus outlined as quite promising; especially, for some determinations in samples with extremely complex matrices (e.g., iodide in non-pretreated and solely diluted urine [334]). As already shown in the previous section 3.4.1., another recently frequent application of CPEs in stripping potentiometry is their use as the electrode support for metallic films; the advantage of application being again that the electrode surface can easily be renewed compared to metallic film electrodes on solid supports [244,247,249,[344][345][346].…”

“…As already shown in the previous section 3.4.1., another recently frequent application of CPEs in stripping potentiometry is their use as the electrode support for metallic films; the advantage of application being again that the electrode surface can easily be renewed compared to metallic film electrodes on solid supports [244,247,249,[344][345][346]. Simultaneously, a series of methods was presented; namely, the determination of lead and cadmium [244,334] or copper [334] when using the MF-CPE configurations, copper and mercury [336] or arsenic [247] at AuF-CPEs, as well as lead and cadmium in parallel at either BiF-CPEs [244,249] or SbF-CPEs [273,337].…”

Differential Pulse Voltammetric and Conductimetric Determination of Diphenylpyraline HCl in Raw Material and Pharmaceutical Preparation

“…All other chemicals used such as acetonitrile, NaTPB and supporting electrolytes (LiClO 4 , Bu 4 NPF 6 and Bu 4 NCl 4 ) were analytical grade reagent (Merk and Fluka). In voltammetric determination the solutions were dearated with purified Argon.…”

“…and the background voltammogram was recorded by scanning the potential toward the positive direction using the selected waveform [5] then 1 ml 5x10 -2 mol/L of the investigated solution was introduced to the electrolysis cell and the produced voltammogram was recorded. The previous procedure has been repeated with both Bu 4 NPF 6 and Bu 4 NCl 4 as supporting electrolytes where the electrode should be polished before each measurement [6].…”