In situ electrochemical monitoring: from remote sensors to submersible microlaboratories

Electrochemical sensors for environmental monitoring: design, development and applications

“…Automatic continuous monitoring of nitrate in rivers, for example, has recently been performed using a novel ion-selective electrode. 60,61 This nitrate-ISE was constructed using immobilized ion exchangers in a rubbery membrane and achieved detections limits on the order of 0.007 mg L 21 . Pioneering studies have shown the effectiveness of ISEs in the in situ monitoring of freshwater and marine sediments.…”

“…conductivity, dissolved oxygen or pH). These have led to a wider range of environmental applications including the measurement of trace metals in natural waters, 8,[16][17][18][19][20][21][22] carcinogen monitoring (e.g. N-nitroso compounds or aromatic amines), 23,24 development of biosensors for the detection of organic pollutants (e.g.…”

In Situ Mapping of H2, O2, and H2O2 in Microreactors: A Parallel, Selective Multianalyte Detection Method

“…At the same time, they enable the continuous acquisition of analyte concentrations in situ. This is rarely offered by other sensing methods, especially when considering additional factors, such as being competitive when it comes to instrumentation size, power, and cost requirements. − Electrochemical sensors are found in a variety of different commercialized applications like monitoring pH, dissolved oxygen, or concentrations of trace metals, carcinogens, and organic pollutants in the environment and in natural and ground water resources. ,− In recent years, their use in a wide range of additional research fields and commercial applications including, but not limited to, biosensors , and sensors for monitoring cell cultures by measuring metabolism markers was driven by a heavy focus on miniaturization and integration in microfluidic and clinical devices, for example, lab-on-a-chip applications. ,− Concentrations of the dissolved gases hydrogen (H 2 ) and oxygen (O 2 ), as well as of hydrogen peroxide (H 2 O 2 ), can be measured amperometrically by their direct oxidation (i.e., H 2 and H 2 O 2 ) or reduction (i.e., O 2 and H 2 O 2 ) on catalytically active noble metal electrodes, such as platinum. Measuring this multianalyte system is however a challenging task considering overlapping oxidation and reduction potentials and therefore superimposed currents, finding electrode materials which are only sensitive to one of the dissolved molecules, and the lack of perm-selective membranes because all molecules are very small and comparable in size.…”