An R script for visualising and analysing fluorescence excitation–emission matrices (EEMs)

Abstract

Fluorescence excitation–emission matrix (EEM) spectroscopy is an important technique for investigating organic material and produces a complex output that often requires further processing for useful analysis. This computer note outlines a tool for producing a range of plots of fluorescence EEM data in the open–source statistical package R. A script has been written that allows the user to input data from Excel worksheets (CSV files) and process multiple input data files. The R script will then produce the plots and summary statistics, in the form of a CSV table, and write the output files to a user specified folder. Plot types include filled contour plots and 3D wireframe perspective plots for whole EEMs, filled contour plots for selected regions within an EEM and plots for specified slices across the EEM. This script provides a free tool to enable the user to rapidly visualise EEMs and produce tailored EEM plots and slices through EEMs of publication quality.