Rapid and Automated Analytical Methods for Redox Species Based on Potentiometric Flow Injection Analysis Using Potential Buffers

Abstract

Two analytical methods, which prove the utility of a potentiometric flow injection technique for determining various redox species, based on the use of some redox potential buffers, are reviewed. The first is a potentiometric flow injection method in which a redox couple such as Fe(III)-Fe(II), Fe(CN)6 3−-Fe(CN)(CN)6 4−, and bromide-bromine and a redox electrode or a combined platinum-bromide ion selective electrode are used. The analytical principle and advantages of the method are discussed, and several examples of its application are reported. Another example is a highly sensitive potentiometric flow injection method, in which a large transient potential change due to bromine or chlorine as an intermediate, generated during the reaction of the oxidative species with an Fe(III)-Fe(II) potential buffer containing bromide or chloride, is utilized. The analytical principle and details of the proposed method are described, and examples of several applications are described. The determination of trace amounts of hydrazine, based on the detection of a transient change in potential caused by the reaction with a Ce(IV)-Ce(III) potential buffer, is also described.

Recent advances in flow injection analysis

“…Over several decades, the evolution of flow injection methodologies with those detections involved optimization of detection flow-through cells, and similarly to general trends in electroanalysis-the search for new electrode materials, employing very different, and especially biochemical molecular recognition mechanisms and development of various techniques of the generation of electrical signal providing analytical information. Those development trends are well illustrated by review papers on detections themselves, [99][100][101][102][103] and their different applications in flow injection measurements, 105,118,146 published in the last decade.…”

Desarrollo de diferentes sensores electroquímicos para la determinación de cloruro

“…Sin embargo, estos análisis son particularmente tediosos cuando la velocidad de la reacción implicada en la valoración es lenta, incluso cuando se usa un valorador automático. Un enfoque prometedor para lograr un rendimiento más rápido para los análisis requeridos en diversos campos, es el acoplamiento de técnicas de flujo a estas técnicas volumétricas [48].…”

“…Once, those points were removed from calibration set, ordinary least square (OLS) Tesis Doctoral regressions were built with the remaining points. The parameters of OLS regressions were used to estimate the detection limit of these sensors for a given probability of false positive (α) and negative (β) of 0.05 [47,48].…”