克服电化学传感方面的挑战:迈向持续监测

Interfacial electrochemical methods focus on the phenomena occurring at the boundary between an electrode and a solution, as opposed to bulk methods that concentrate on the solution's overall properties. These interfacial methods are classified as either static or dynamic based on the presence of a nonzero current in the electrochemical cell and the consistency of analyte concentrations. Static methods, such as potentiometry, measure the cell's potential without any significant current...

 Electrochemical measurements are conducted in an electrochemical cell composed of various components that control and measure the current and potential. One fundamental component is electrodes, conductive materials that enable electron transfer reactions at their surfaces.
There are two main types of electrodes in electrochemical cells. The first type, known as the working or indicator electrode, has a potential that is sensitive to the analyte's concentration and reacts to changes in...

Membrane electrodes, also known as p-ion electrodes, use membranes that selectively interact with free analyte ions, generating a potential difference across the membrane. The resulting membrane potential, known as the asymmetry potential, is not zero even when analyte concentrations on both sides of the membrane are equal. The membrane's response is typically not selective to a single analyte but proportional to the concentration of all ions in the sample solution capable of interacting at...

Reference electrodes serve as a stable reference point for potentiometric measurements, while indicator and working electrodes react to variations in the composition of a solution.
The Standard Hydrogen Electrode (SHE) is a widely used reference electrode that maintains zero potential across all temperatures. However, its need for a continuous hydrogen gas supply renders it impractical for everyday use.
An alternative to SHE is the Saturated Calomel Electrode (SCE). This electrode features an...

Amperometry is a technique commonly used to measure the concentration of specific analytes in a solution by monitoring the electric current generated during an electrochemical reaction. It involves applying a constant potential between a working electrode and a reference electrode to measure the resulting current, which is proportional to the concentration of the analyte. The Clark oxygen electrode operates based on this principle of amperometry. It consists of a cathode and an anode enclosed...

Controlled-potential coulometry, also known as potentiostatic coulometry, employs a three-electrode system in which the working electrode's potential is precisely regulated using a potentiostat. Platinum working electrodes are utilized for positive potentials, while mercury pool electrodes are favored for extremely negative potentials. The platinum counter electrode is separated from the analyte using a membrane or salt bridge to avoid interference in the analysis.
The chosen potential...