The Proteus is a new product launched by Proteus instruments providing users with a robust,repeatable, low maintenance sensor platform for measuring DOC in real-time. The Proteus is underpinned by comprehensive research exploring the use of in-situ fluorescence as a technique for real-time DOC measurement. The Proteus for DOC monitoring (See Fig. 1) is a multi-parameter instrument that incorporates a CDOM fluorometer, turbidity sensor and thermistor to provide real time measurement of the bulk dissolved organic load, negating the need for couriers and laboratory analysis. Using a robust correction algorithm the CDOM signal is corrected, in real time, for temperature interference. The result is a repeatable measurement that can provide instantaneous DOC measurement with a simple site specific calibration for turbidity and CDOM relationship with DOC (Fig. 3).
Fluorescence spectroscopy is a selective and sensitive optical technique enabling in-situ,real-time measurement of dissolved organic matter. Molecules absorb light of a specific wavelength and orbiting electrons are excited to a higher energy state .The electrons then emit light of a specific wavelength to return to the base state.
The dissolved organic matter pool can be mapped in optical spaced based on its fluorescent properties (see Fig. 2). A subset of the coloured dissolved organic matter (CDOM) pool is fluorescent and has a distinct fluorescence peak (Fig.2). This peak is primarily associated with humic and fluvic acids, the by-products of microbial degradation of vascular plant material. The intensity of the CDOM fluorescence signal, often reported in quinine sulphate (QSE) units, is strongly correlated to DOC concentration and TOC. Numerous published studies from a wide range of geographical locations have correlated CDOM fluorescence with DOC and our site-specific calibrations can provide users with accurate and highly repeatable measurements.