You are here:
Preliminary assessment of IRMS and FTIR for characterization of microplastics
Citation:
Birch, Q., S. Al-Abed, P. Pinto, P. Potter, AND D. Dionysiou. Preliminary assessment of IRMS and FTIR for characterization of microplastics. 257th ACS National Meeting, Orlando, Florida, March 31 - April 04, 2019.
Impact/Purpose:
The environmental impact of microplastics has gained a lot of attention in recent years. Their fate and transport and their impact in marine and aquatic life has been studied, but the characterization and monitoring methods need to be further developed and standardized. In this study, we investigate the feasibility of using isotope ration mass spectrometry (IRMS) and Fourier transform infrared (FTIR) spectroscopy were used as complementary methods to characterize common plastics. Preliminary results showed that IRMS has the potential to differentiate petroleum-derived from plant-derived polymers, while was not affected by the dyes present in the plastic. This could be the first step to develop a method to differentiate polymers found in the environment and link them to their sources. That would be an important step to focus the reduction efforts on the plastics most commonly found in different ecosystems. This research could be of interest for the environmental research community, academia, environmentalists and all those involved in the plastic industry.
Description:
Abstract: Plastic is a persistent and growing environmental pollutant. Small (largest crosswise dimension <5 mm) particles called ‘microplastics’ (MPs) are of special concern because they have been found to disrupt marine ecosystems globally. The presence of MPs contaminating freshwater and terrestrial systems has also been reported. It has been assumed that marine contamination is mainly of terrestrial origin, but systematic studies of its sources are lacking. An absence of standardized characterization and monitoring methods has slowed the progress of understanding the sources, transport, and impact of MPs into the environment. In this study, stable carbon isotope ratio mass spectrometry (IRMS) and Fourier transform infrared (FTIR) spectroscopy were used as complementary methods to characterize common plastics. In IRMS, carbon isotopic ratios (13C/12C) for materials are expressed relative to the ratio of a standard, as δ13C values. This technique has previously been applied to determine the origin of organic matter in the environment. Based on preliminary results, IRMS seems to be a promising tool for MP analysis. The δ13C values for petroleum- and plant-derived materials reflected their sources, while recycled materials had values between these two. Dyes in the plastics did not appear to affect the δ13C results, an advantage over spectroscopic methods. Other advantages of IRMS for MP analyses are high sensitivity; fast, automated analyses; and low cost. Disadvantages relative to FTIR-based methods are that IRMS is not a confirmatory technique, and it is destructive.