Electrochemical Sensors Developed for Gathering Microscale Chemical Information

Abstract

Miniaturization is a broad trend that has been observed in various areas of technology. As a result of the intensive high tech research efforts of the past few decades in the electronics and telecommunication industries, different tools and technologies have been developed for creating highly structured miniaturized parts and units. These tools and technologies have also been employed for producing special miniaturized units for use in chemical analysis. Miniature sensors, flow micro channels, and detectors are becoming widespread devices in analytical laboratories. The lab-on-a-chip concept is gaining acceptance for a variety of applications.In many different areas of experimental science, researchers endeavor to collect chemical information with high spatial resolution about various subjects. Miniaturized electrochemical sensors and micro or ultramicro electrodes can be used for this purpose. A variety of microelectrodes have been developed and used to collect chemical information in the last few decades. Life scientists, who were studying various biochemical processes inside living tissues with microelectrodes, were pioneers in this work. Recently, a powerful new technique for collecting high resolution chemical information has been devised. This method is known as "scanning electrochemical microscopy." Scanning electrochemical microscopy relies on the electrochemical micro-measuring tip. In this short review, the properties of these microelectrodes are discussed briefly, and the types of ion-selective microelectrodes and voltammetric electrodes developed by several research groups for gathering high resolution information are introduced.

Scanning electrochemical microscopy for the investigation of corrosion processes: Measurement of Zn2+ spatial distribution with ion selective microelectrodes

“…Scanning electrochemical microscopy can also be operated in a potentiometric mode by employing an ion-selective microelectrode (ISME) as the tip [32][33][34][35]. They present higher chemical selectivity than conventional amperometric microdisks, and may be the only effective option to visualize the dissolution of metals with negative redox potentials in aqueous environments when the use of Pt microelectrodes is limited by the onset of oxygen reduction and hydrogen evolution reactions [36,37].…”

A novel microelectrochemical strategy for the study of corrosion inhibitors employing the scanning vibrating electrode technique and dual potentiometric/amperometric operation in scanning electrochemical microscopy: Application to the study of the cathodic inhibition by benzotriazole of the galvanic corrosion of copper coupled to iron

“…In the first case, non-aqueous environments had to be employed for the investigation of the electrochemical reactivity of the metallic systems [13,14], whereas higher chemical selectivity would be required to solve the later. This is the reason to investigate the applicability of the potentiometric operation in SECM [17,18] for the study of corrosion reactions [19], though from a practical point of view, it is very difficult to control the tip-sample distance in this case. A very promising way to combine the advantages of amperometric and potentiometric operation modes in SECM has arisen from the introduction as UME tips of materials that exhibit a dual-function in different potential ranges [20,21].…”

Determination of Microcystin-LR in waters in the subnanomolar range by sol–gel imprinted polymers on solid contact electrodes

“…Only electrodes of solid contact are considered because they are easily adapted to chip-based devices (highly desired in local monitoring operations) by coating a solid conductive layer with the selective membrane. 28,29 All prepared sensors are evaluated, characterized and applied.…”