Platform for Microdebris Capture and Raman Analysis from Liquid Sources Using Silicon Nanomembranes

Session: Microplastics in Freshwater Systems: Advances in Chemistry, Biology and Physics (1)

Gregory Madejski, University of Rochester, [email protected]
James McGrath, University of Rochester, [email protected]
Dan Yu, University of Rochester, [email protected]
Wayne Knox, University of Rochester, [email protected]

Abstract

Microplastics (100 nm – 5 mm) are found in a majority of natural environments, but are also present in foods, beverages, and municipal water supplies. Due to the heterogeneity of particulates in a sample, it is difficult to quickly and accurately visualize the contaminants and concurrently determine their composition. While there are many methods that are employed to measure particles, they aren’t necessarily timely, convenient, or easy to use. Our analysis methodology utilizes ultrathin high-performance silicon nitride filters and Raman microspectroscopy, to characterize particles by shape, size, and material composition. By filtering 500 mL of water using a nanomembrane (8-9 µm slot width, 400 nm thick), we can capture a range of microdebris on a plane for visualization and analysis. The thinness and transparency of the nanomembrane permits in situ imaging of the contaminants and the suspension of particles over the slots creates an ideal situation to measure only the Raman fingerprint of the materials, individually assessing all captured particles. We believe a combination of microfiltration (currently 15 mL/min, gravity filtration), capture, and Raman analysis will increase the speed, quality, and enumeration of microdebris contamination in a variety of heterogeneous liquid sources.