Microplastics are present in surface water samples taken from Cayuga Lake, NY. We estimate that there are close to 100 million plastics in the lake. The presentation will cover what we have discovered by using Raman Mass Spectroscopy (RMS) as well as pros and cons alongside the methods which include identification, interference from dyes and other additives to plastics, the importance of specific Raman settings, and considering the spectra of glass and mounting solutions. Our current RMS configuration is as follows: we currently use the WITec Alpha300R Confocal Raman Microscope as our main driver. We have two laser options, 532 λ and 750 λ. Due to fluorescing and noise, we have found the 532 λ is more reliable. We always set laser power to a low grade to avoid particle burn. We adjust laser power depending on particle thickness. We use a CaCl<sub>2 </sub>mounting solution to mount particles to a glass slide before spectral capture. During the capture of the spectra at 20X, particles respond best to 10 accumulations and an integration time of 10.0 seconds. Before baseline adjustment, we usually see a spectra that is too noisy to match in the spectral database. After baseline adjustment, we normally see definitive results. Adjustments are made in ProjectFive, a Raman data processing suite. We then compare our spectra to those in a spectral database (KnowItAll – Wiley Library) to seek matches. We will share what we are finding and why it is an important addition to microplastics research.

Microplastic verification using Raman mass spectroscopy – configurations & outcomes

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.