Validation of ATR FT-IR to identify polymers of plastic marine debris, including those ingested by marine organisms

• Published in: Marine pollution bulletin Vol. 127; pp. 704 - 716
• Main Authors: Jung, Melissa R., Horgen, F. David, Orski, Sara V., Rodriguez C., Viviana, Beers, Kathryn L., Balazs, George H., Jones, T. Todd, Work, Thierry M., Brignac, Kayla C., Royer, Sarah-Jeanne, Hyrenbach, K. David, Jensen, Brenda A., Lynch, Jennifer M.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-02-2018; Elsevier BV
• Subjects: Analytical methods; Animals; Chromatography; Cleaning; Debris; Eating; Environmental Monitoring - instrumentation; Environmental Monitoring - methods; Fourier transform infrared spectroscopy; Fourier transforms; Gastrointestinal Contents - chemistry; High density polyethylenes; High temperature; Identification; Identification methods; Infrared spectroscopy; Low density polyethylenes; Marine debris; Marine organisms; Marine plastic debris; Molecular Structure; Pacific Ocean; Plastic ingestion; Plastics; Plastics - analysis; Polyethylene; Polymer identification; Polymers; Polypropylene; Polystyrene; Polystyrene resins; Polyvinyl chloride; Reflectance; Reptiles & amphibians; Sea turtles; Sensitivity and Specificity; Size exclusion chromatography; Spectroscopy, Fourier Transform Infrared; Studies; Turtles; Turtles - metabolism; United States; Waste Products - analysis; Water pipes; Water Pollutants, Chemical - analysis; Pacific Ocean; Fourier transform infrared spectroscopy; Plastic ingestion; Marine plastic debris; Polymer identification; Sea turtles
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2017.12.061

Polymer identification of plastic marine debris can help identify its sources, degradation, and fate. We optimized and validated a fast, simple, and accessible technique, attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR), to identify polymers contained in plastic ingested by sea turtles. Spectra of consumer good items with known resin identification codes #1–6 and several #7 plastics were compared to standard and raw manufactured polymers. High temperature size exclusion chromatography measurements confirmed ATR FT-IR could differentiate these polymers. High-density (HDPE) and low-density polyethylene (LDPE) discrimination is challenging but a clear step-by-step guide is provided that identified 78% of ingested PE samples. The optimal cleaning methods consisted of wiping ingested pieces with water or cutting. Of 828 ingested plastics pieces from 50 Pacific sea turtles, 96% were identified by ATR FT-IR as HDPE, LDPE, unknown PE, polypropylene (PP), PE and PP mixtures, polystyrene, polyvinyl chloride, and nylon.
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•We validate ATR FT-IR to identify polymers of weathered and ingested plastics.•We outline criteria to differentiate HDPE from LDPE samples.•Cutting or cleaning ingested plastics with water improves identification.•A database of standards is not required for polymer identification.•Collaborations of life and materials sciences address plastic debris issues.