Fiber-optic imaging for in-situ chemical measurements

Fiber-optic imaging sensors are being developed for in-situ chemical measurements using microfiber image guides. Applications of particular interest are analyte transport in thin membranes and ion transport in electrochemical boundary layers. We have demonstrated that microfiber image guides can be used for in-situ transport studies of analyte transport in thin membranes and for ion transport at electrode boundary layers in a working electrochemical cell. We have also shown that imaging sensors can be made by coating the image guide with pH sensitive and other ion-sensitive fluorescent indicator molecules, and that these sensors can be used to measure the time development of concentration gradients in-situ. Finally, it is demonstrated that these techniques can be used to obtain fundamental transport information such as diffusion coefficients in-situ at the microscopic level. Image guide sensors are described here along with a discussion of preliminary transport studies.