Abstract

Transparent windows used to perform optical measurements in `difficult' samples such as natural waters in the environment and sewage streams in treatment plant inevitably become coated with chemically and/or biologically deposited films. These usually dominate the instrument's performance and reliability. We describe here a windowless measurement configuration, which avoids this fouling by supporting the water sample from below on an air bubble. By controlling the air pressure in the bubble with a fast pressure-modulator and feedback controller, the air-water meniscus' curvature is stabilized, and serves as a reliable optical interface to the liquid medium. Round menisci up to 8 mm in diameter have been stably controlled, with electronically regulated curvature. By periodically purging the bubble with air, long-term measurements of scattering and long-path absorption are possible, substantially free from fouling problems.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.