Collaborative Research: Application of fluorescence spectroscopy for the characterization of dissolved organic matter: Disentangling common misconceptions and underlying chemistry

溶解有机物（DOM）是一种复杂的含碳分子的混合物，存在于所有的水生环境中。DOM在水生态系统中起着重要的作用。因此，DOM化学成分的变化可能有助于了解环境中的不同过程。荧光已成为表征DOM的常用工具，但许多挑战与其使用相关。在博尔德的科罗拉多大学和蒙大拿州立大学之间的这项研究合作中，将评估DOM的荧光特性与该混合物中特定化学成分之间的联系。这项研究的结果将影响环境工程和水产科学领域提供具体的指导方针和教育有关使用荧光作为一个广泛的度量DOM化学理解在水生生态系统。 利用荧光光谱技术对溶解性有机物（DOM）进行表征已成为环境工程和科学界普遍关注的问题。具体而言，使用激发发射矩阵（EEMs）已成为研究人员在众多自然和工程过程中检查DOM的最常用工具之一。鉴于EEM中收集的数据量，已经开发了几种定性和定量方法来分析结果。在大多数情况下，这些方法试图将荧光响应与DOM内的化学成分或行为联系起来。环境工程和科学界已经接受荧光作为表征DOM的重要工具。然而，在了解哪些具体因素（例如，化学结构和分子组成）控制观察到的荧光响应。该项目的主要目标是通过对荧光分析进行详细评估，以填补荧光信息化学解释的不足，作为解释DOM化学成分和可变性的广泛措施。该提案的结果将为工程师和科学家提供有关使用荧光表征DOM的指导方针。使用不同的常用荧光解释指标将校准对不同的化学分析DOM样品从高荧光环境馏分。预计该项目将为社区提供关于在自然和工程系统中使用荧光进行DOM研究的限制的详细指南。教育部分将侧重于将这项研究的结果纳入合作机构的大学课程和部门研讨会。研究生和本科生将接受常规用于水质评估的分析化学技术的教育。他们还将学习分子水平上的高级分析DOM表征技术。荧光社区将通过在国内和国际科学会议上组织的会议以及在高影响力科学期刊上的出版物了解这项工作的结果。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dissolved organic matter (DOM) is a complex mixture of carbon containing molecules that are present in all aquatic environments. DOM plays an important role in aquatic ecosystems. Thus, variations in DOM chemical composition may inform understanding of different processes in the environment. Fluorescence has emerged as a common tool to characterize DOM, but many challenges are associated with its use. In this research collaboration between the University of Colorado at Boulder and Montana State University, the connection between fluorescence characterization of DOM and specific chemical constituents within this mixture will be evaluated. The results from this study will impact the field of environmental engineering and aquatic science by providing specific guidelines and education regarding the use of fluorescence as a broad metric for DOM chemical understanding in aquatic ecosystems. The characterization of dissolved organic matter (DOM) by fluorescence spectroscopy has become ubiquitous in the environmental engineering and science communities. Specifically, the use of excitation emission matrices (EEMs) has emerged as one of the most common tools used by researchers examining DOM on numerous natural and engineered processes. Given the amount of data collected in an EEM, several qualitative and quantitative approaches have been developed to analyze the results. In most cases, these approaches attempt to tie a fluorescence response to a chemical constituent or behavior within DOM. The environmental engineering and science community has embraced fluorescence as an important tool for the characterization of DOM. However, little progress has been made in understanding what specific factors (e.g., chemical structures and molecular composition) controls the observed fluorescence response. The main goal of this project is to fill the deficiencies in chemical interpretations of fluorescence information by conducting a detailed evaluation of fluorescence analyses as a broad measure to interpret the chemical composition and variability of DOM. The results from this proposal will offer guidelines to engineers and scientists regarding the use of fluorescence for the characterization of DOM. The use of different commonly used fluorescent interpretation metrics will be calibrated against distinct chemical analyses of DOM samples from highly fluorescing environmental fractions. It is expected that this project will provide the community with detailed guidelines regarding the limitations of the use of fluorescence for DOM research in natural and engineered systems. The educational component will focus on the incorporation of results from this study into collegiate curricula and departmental seminars at the collaborating institutions. Graduate and undergraduate students will be educated in analytical chemistry techniques routinely used for water quality assessments. They will also learn advanced analytical DOM characterization techniques at the molecular level. The fluorescent community will be informed of the results from this work via convened sessions organized at domestic and international scientific conferences and publications in high impact scientific journals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.