We demonstrate that the fluorescence spectrum from water droplets containing the dye acridine can be used to accurately determine the pH of droplets in the radius range 15-60 mum and in the pH range 3-10. Using a laser pump wavelength of 355 nm and probing the fluorescence with a 0.5 m spectrograph and CCD detector. the particle size parameters are sufficiently large in this radius range that the fluorescence spectrum conforms to that of the bulk phase, permitting a direct unambiguous determination of droplet pH. This could provide a sensitive method for studying directly the uptake of acidic or basic reagents on aerosol droplets. (C) 2002 Published by Elsevier Science B.V.
|Article number||PII S0009-2614(02)00529-0|
|Number of pages||8|
|Journal||Chemical Physics Letters|
|Publication status||Published - 3 May 2002|
- MORPHOLOGY-DEPENDENT RESONANCES
- OPTICAL PROCESSES