Application of a multi-method approach in characterization of natural aquatic colloids from different sources along Huangpu River in Shanghai, China

Natural colloid properties and the impact of human activities on these properties are important considerations for studies seeking to understand the fate and transport of pollutants. In this study, the relationship between size and fluorescence properties of natural colloids from 4 different sources were quantified using a multi-method analytical approach including UV-visible and fluorescence spectroscopy, flow field flow fractionation (FlFFF) coupled online to fluorescence spectrometer, and atomic force microscopy (AFM). Results indicate that colloids from pristine natural river water have higher aromaticity and humification, higher fluorescent intensity, and smaller size compared to those from the rivers impacted by livestock. The majority of colloids are smaller than 10nm in size as measured by AFM and FlFFF. Colloid size measured by FlFFF coupled to fluorescence spectroscopy increases in the order peak C (Ex/Em at 300-340/400-460 nm)