An article published on April 27, 2017 presented a sensor array for detection of organic and inorganic contaminants in recycled plastics. Nathan Davis and colleagues from the Polymer and Food Protection Consortium, Iowa State University, U.S., constructed and tested a system enabling “on-line and real-time analysis of recycled food contact surfaces during the conversion process for quality assessment of the finished products.” The system uses a combination of proprietary sensors based on “photoionization, energy dispersive x-ray fluorescence and gas flame ionization detection,” coupled to a computational predictive model.

The system was tested in a polyethylene terephthalate (PET) recycling process for analyzing the levels of inorganic (metals) and organic (volatile contaminants such as ethylene glycol, acetaldehyde, and phthalates) contaminants, and sensor measurements were shown to correspond to determinations made by traditional analytics methods.

The authors concluded that “the sensor array and predictive models designed for this research can be used to evaluate organic and inorganic contaminate loads during the conversion process, and provide consistent data that correlates to traditional validation techniques in contamination analysis.” It can be used as a “tool for evaluating compliance,” allowing for “real-time decision and diversion strategies during the conversion of resin and flake to final articles or products to minimize any negative impact on human health and environmental exposure.”


Davis, N., et al. (2017). “Sensor array for detection of organic and inorganic contaminants in post-consumer recycled plastics for food contact.Food Additives & Contaminants: Part A (published April 27, 2017).