Characterization of Chromophoric Dissolved Organic Matter (CDOM) in Rainwater Using Fluorescence Spectrophotometry

The fluorescence excitation-emission matrix of Chromophoric dissolved organic matter (CDOM) samples from rainwater collected at Rameswaram, Tamilnadu, India are analysed. Total five peaks were observed for humic/marine and protein likes substances respectively. The peak A and C intensities varies form 1.98 +/- A 0.28 and 0.97 +/- A 0.11 QSU respectively represents humic like substances. The peak B and T intensities varies from 3.94 +/- A 0.75 and 7.42 +/- A 1.43 QSU showed association of protein like substances whereas peak M intensities varies from 1.92 +/- A 0.37 QSU indicates marine contribution. Among the fluorophores, the following sequence were observed as T > B > A > M > C which indicates dominance of Tryptophan like substances in rainwater. The average peak T/C ratios was observed as 7.88 +/- A 2.2 indicates microbial contamination by Tryptophan-like substances with the high biological activity and low volatility.