Determining optical absorption of colored dissolved organic matter in seawater with a liquid capillary waveguide

Show full item record

Redirect: RIT Scholars content from RIT Digital Media Library has moved from to RIT Scholar Works, please update your feeds & links!
Title: Determining optical absorption of colored dissolved organic matter in seawater with a liquid capillary waveguide
Author: D’Sa, Enrico; Steward, Robert; Vodacek, Anthony; Blough, Neil; Phinney, Dave
Abstract: Optical absorption spectra of 0.2- um filtered sea-water samples originating from diverse oceanic and coastal waters were measured with a long pathlength capillary wave-guide; results were compared with those of three different lab-oratory spectrophotometers. The 0.5-m long 550- um (inside diameter) aqueous waveguide uses only 120 ml of filtered sea-water, making it convenient for use in flow-through cells or when sample volumes are restricted. Source light propagates inside the capillary waveguide by total internal reflection because of the lower refractive index of the waveguide walls with respect to the aqueous core. The absorption coefficient of colored dissolved organic matter (CDOM) at 355 nm and S, the slope of the log linearized CDOM absorption spectra, were determined for all samples. The CDOM absorption spec-tra measured by the capillary waveguide closely matched that measured by spectrophotometers for CDOM concentrations varying over an order of magnitude. The deviations between the absorption spectra obtained with the capillary waveguide and those obtained with the standard spectrophotometers increased with decreasing total absorption and with increase in wavelength, presumably because of the greater baseline offsets observed in the capillary waveguide. The offsets are due to differences in refractive indices between the seawater samples and the freshwater reference. With a suitable reference, the capillary waveguide will be very useful for monitoring surface seawater CDOM absorption semicontinuously.
Description: This article may be accessed from the publisher's website (additional fees may apply) at: community members may access full-text via RIT Libraries licensed databases:
Record URI:
Date: 1999-06

Files in this item

Files Size Format View
LimnologyOceanographyCopyrightPolicies.pdf 60.84Kb PDF View/Open

The following license files are associated with this item:

This item appears in the following Collection(s)

Show full item record

Search RIT DML

Advanced Search