Chemical Characterization of Microplastics Polymers with a Novel Technique of Pyrolysis GC-MS



Ashok Deshpande



The weathering related degradation of large marine plastic fragments due to the exposure to wave action, ocean-currents, solar UV radiation, suspension, and resuspension results in a progression of changes that include the loss in mechanical integrity, embrittlement, and further fragmentation into micro-sized plastic commonly referred to as the microplastics. Our recent interest has expanded in the chemical characterization of microplastics polymers with the use of a novel technique of pyrolysis GC-MS. In this method, a small piece of plastic, less than 1 mg, is placed in a narrow quartz tube. The quartz tube is heated in a platinum coil at 750C and the pyrolyzed products are transferred to the GC-MS. The fragmentation patterns of plastic polymers have been reported to be reproducible and quite unique to a given polymer. The information on polymer chemistry will help the management in the identification of the possible plastic products and perhaps in the mitigation, control, and monitoring of the status and trends of plastic pollution. The different polymers exert different toxicities and different polymers adsorb contaminants to different extents. The triple threat of plastic toxicity, contaminant toxicity, and nutritional challenge is an area of concern in the management of fisheries resources and the endangered species. We have developed a baseline library of pyrolysis GC-MS spectra of the commonly used plastic polymers. Currently we are testing the proof of concept of this novel method in the routine household and laboratory plastic items and the broken pieces of plastics from the field collections. The results so far are very encouraging.