The stability of the detection cell components is another concern, depending on the type of analysis. Good sensitivity often requires dual electrode configurations. Small volumes in the separation capillaries in Capillary Electrophoresis require that the detector be placed in-line to minimize line broadening. Amperometric postcolumn detection of Cys and Hcy may suffer from low selectivity and high background current as Cys exhibits irreversible oxidation requiring positive overpotential. Electrochemical detection of thiols by Capillary Electrophoresis requires precision electrode alignment and isolating the detector from the separation voltage. Escobedo, in Comprehensive Supramolecular Chemistry II, 2017 8.20.1.1.1 Electrochemical methodsĮlectrochemical detection may be complicated by interference from oxidizable impurities. Air bubbles in the carrier stream and electrode fouling, requiring periodic calibration and renewing of the surface, create problems. The detection limit in potentiometric measurements is lower than in batch methods.
Electrochemical-stripping analysis is used mainly in the determination of amalgam forming metal ions. In conductometric as well as in potentiometric and voltammetric measurements, the response is related to the concentration or activity of the analyte and can be evaluated by using calibration curves. The electrochemical detection methods discussed in the chapter are conductometric, potentiometric, voltammetric, amperometric, and coulometric measurements. The classification of electroanalytical techniques is provided. The electroanalytical techniques can be divided into different groups depending on the electrical signal that is measured. This chapter discusses electrochemical detection in sequential injection analysis (SIA) and describes the achievements in the application of different electrochemical detection methods. The detector design with the electronics can be simple and compact, allowing the construction of portable instruments, especially when conductometric, potentiometric, and amperometric detection is used. Ari Ivaska, in Comprehensive Analytical Chemistry, 2008 Publisher SummaryĮlectrochemical detection in flow analysis has several advantages and disadvantages.
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