ESEL Paper Review_20110223 by Aamir Alaud-din

1.    Title and Author

Title: 2011_02_23_Fluorescence Fingerprint of Waters: Excitation-Emission Matrix Spectroscopy as a Tracking Tool
 
Authors: Yuan Yan1, Hong Li2, M. L. Myrick*

1Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208

2Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208

*Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208

2.    Summary of Paper

There is a lot of chemical information in rivers and harbors because of the direct interaction with human activities. A study of mixing of two rivers (Saluda and Broad Rivers mix in Congaree River) was carried out. Sampling site A is situated in Saluda River, site B in Broad River while sites C, D, and E are located in Congaree River.

Excitation-emission matrix (EEM) spectra were scanned. The samples were examined with wavelengths from 200 to 290 nm in 10 nm steps. Emission wavelengths ranged from 300 to 600 nm with a step of 1 nm. 

Two types of fluorophores were found: (1) hummic acid-like at 420 ? 450 nm emission wavelength when excited with 230 ? 260nm and 320- 350nm; and (2) protein or amino acid-like at 300 ? 305nm and 340 ? 350nm when excited with 220 and 275nm wavelengths. Since the water samples were from two different sources, so, the artificial mixtures from samples collected from two sources were prepared and analyzed. The results showed that mixing of two samples leaves chemistry of mixture nearly unchanged as shown in table below.
Table - Composition of artificial mixtures of Saluda and Broad River water by PCR (two components)
Saluda, % Actual    Saluda, % predicted    Broad, % predicted
10.0    10.0    89.8
30.0    31.5    67.1
50.0    49.3    51.9
70.0    72.0    28.9
90.0    89.6    10.3

Results of temperature differences and PCR revealed a lack of mixing of two rivers just below the confluence of Saluda and Broad Rivers. Mixing occurred two miles below the confluence point of the two rivers.

3.    Contribution to ESEL

This paper shows that the statistical models help in the study in complex conditions. Statistical study enabled to study mixing of two rivers which is very difficult with mathematical models.

By: Aamir Alaud-din
aamiralauddin@gist.ac.kr