Modern directions for potentiometric sensors

Abstract

Este artigo apresenta uma revisão dos mais recentes progressos dos eletrodos íons-seletivos de membrana polimérica. É discutida uma essência curta da teoria básica, enfatizando como a força eletromotriz pode ser usada para calcular as constantes de ligação do ionóforo, e como a seletividade e o limite de detecção estão relacionados aos processos de membrana mais importantes. Os recentes progressos na diminuição dos limites de detecção dos ISEs são descritos, incluindo recentes tentativas no desenvolvimento de ISEs de contato sólido, e inovações na detecção de quantidades ultra-pequenas de íons em baixas concentrações. Esses progressos têm alçado o caminho para usar sensores potenciométricos em bioanálise com afinidade ultra-sensível junto com nanopartículas usadas como marcadores. Os resultados recentes estabelecem que a potenciometria compara-se favoravelmente com a análise de redissolução eletroquímica. Outros novos progressos com os eletrodos de íon-seletivo são também descritos, incluindo o conceito de potenciometria de calibração interna, coulometria de corrente controlada, cronopotenciometria pulsada, e titulação rápida localizada com membranas íon-seletivas para desenhar sensores de detecção direta da acidez total sem perturbação da amostra. Estes progressos têm aberto um amplo campo para novos desenvolvimentos e aplicações nesta área. This paper gives an overview of the newest developments of polymeric membrane ion-selective electrodes. A short essence of the underlying theory is given, emphasizing how the electromotive force may be used to assess binding constants of the ionophore, and how the selectivity and detection limit are related to the basic membrane processes. The recent developments in lowering the detection limits of ISEs are described, including recent approaches of developing all solid state ISEs, and breakthroughs in detecting ultra-small quantities of ions at low concentrations. These developments have paved the way to use potentiometric sensors as in ultra-sensitive affinity bioanalysis in conjunction with nanoparticle labels. Recent results establish that potentiometry compares favorably to electrochemical stripping analysis. Other new developments with ion-selective electrodes are also described, including the concept of backside calibration potentiometry, controlled current coulometry, pulsed chronopotentiometry, and localized flash titration with ion-selective membranes to design sensors for the direct detection of total acidity without net sample perturbation. These developments have further opened the field for exciting new possibilities and applications.

Used gold nano-particles as an on/off switch for response of a potentiometric sensor to Al(III) or Cu(II) metal ions

“…The inherent selectivity of these devices is attributed to highly selective interactions between the membrane materials and the target ion. Many ion selective electrodes are commercially available and routinely used in various fields [1][2][3][4][5][6][7].…”

Determination of pethidine hydrochloride using potentiometric coated graphite and carbon paste electrodes

“…In a coated‐wire electrode, the polymer membrane is directly cast on the solid surface, with no internal reference solution being interposed. This type of sensors eliminated the internal filling solution provides new advantages, for instance, good mechanical stability, simplicity, and possibility of miniaturization 24…”

“…This type of sensors eliminated the internal filling solution provides new advantages, for instance, good mechanical stability, simplicity, and possibility of miniaturization. [24] CPE are mixtures prepared from graphite powder and various water-immiscible organic liquids of non-electrolytic character packed at the end of a teflon holder in contact with a copper wire thus eliminating internal solution. CPE have several advantages such as chemical inertness, robustness, renewability, stable response, low ohmic resistance and no need for internal solution.…”

Determination of Listeria Monocytogenes in Milk Samples by Signal Amplification Quartz Crystal Microbalance Sensor

“…Many methods have been developed including optimizations of probe immobilization on electrodes (Bakker and Chumbimuni-Torresb 2008) and various signal amplification strategies using non-specific amplifiers of anti-dsDNA antibodies (Wei et al 2008), liposomes (Nikolelis, Petropoulou, and Mitrokotsa 2002), enzymes (Treu and Minteer 2008), and nanoparticles (Zhao et al 2001;Choi and Kim 2008;Stringera et al 2008;Chen et al 2008;Lin et al 2007;Yang, Yuan, and Chai 2008;Du, Che, and Cai 2008). Among these strategies, metallic colloid nanoparticles have been successfully applied to sensors because of their easily controllable-size distribution, long-term stability, and friendly biocompatibility, and many ingenious schemes were designed and the performances of sensors were improved dramatically (Gu et al 2006).…”