Research Symposium

BIO

Lexa Kooistra is a sophomore student at Florida State University pursuing a Bachelor of Science in Biochemistry with minors in Biological Sciences and Linguistics. Originally from Windermere, Florida, Kooistra conducts research under Dr. Ming Ye, where she is working to develop a lake-specific organic carbon correction factor for nitrate concentration determination with UV-Vis spectrophotometry. Her work aims to support efficient and cost-effective nutrient level monitoring, contributing to broader efforts to improve water quality and combat eutrophication in lake systems. Through this research, she has gained experience in environmental chemistry, spectrophotometric analysis, and data interpretation. Kooistra is a member of the Florida State University Honors Program and a recipient of the Vires scholarship. She is also involved in organizations such as Tri-Beta Biological Honor Society, Connecting Experimental Lab and Life Sciences (CELLS), and FSU Fencing Club. After earning her Bachelor of Science, Kooistra plans to pursue graduate school, followed by a career in the biotechnology industry, with interests in specific sectors such as pharmaceutical development, genetics research, and environmental management.

Developing a Lake-Specific DOC Correction Factor for Nitrate Determination with UV-Vis Spectrophotometry

Abstract

Excess nitrate (NO3-N) contributes to eutrophication, a process that produces ecosystem-degrading algal blooms. Researchers often utilize UV-Vis spectrophotometry to measure the concentration of nitrate in natural waters, but this method is constrained by interference from naturally occurring dissolved organic carbon (DOC). This research aims to develop a specific DOC correction factor for Lake Munson UV-Vis nitrate determination, based on the methods described in Edwards et al. (2001). Water samples were collected from multiple sites in Lake Munson and analyzed with UV-Vis spectrophotometry at 205 and 300 nm. The DOC correction factor for Lake Munson was derived from regression analysis of DOC-modelling standard solutions between these two wavelengths. For validation, the nitrate concentration determined using the DOC value was referenced against direct measurements from ion chromatography and cadmium reduction. This research is currently ongoing, and future plans include refining the correction value with additional Lake Munson sampling. This project offers a streamlined framework for UV-Vis nitrate measurements in lake water, supporting more reliable and rapid nutrient monitoring for specific lake systems and, in turn, aiding water quality improvement efforts against eutrophication.

Keywords: UV-Vis Spectrophotometry, Water Quality, Environmental Science