Rapid detection of microplastics and nanoplastics in seconds by mass spectrometry

Microplastics (MPs) and nanoplastics (NPs) are pervasive pollutants and their analyses by traditional mass spectrometric methods require time-intensive sample preparation (e.g., extraction, digestion, and separation). This study presents a rapid and novel method for detecting MPs and NPs using flame ionization mass spectrometry (FI-MS) in which a dried sample (e.g., powder, soil and tissue) is directly burnt or heated with a flame in front of the MS inlet. FI-MS enables decomposition and ionization of various plastics such as polyethylene terephthalate (PET) and polystyrene (PS), allowing for analysis to be completed as fast as 10 seconds per sample. As a demonstration of application of this technique, PET contaminants in 1 L of bottled water or in 0.65 L of apple juice contained in plastic bottles were quickly detected from a filter paper after sample filtration and brief drying. A 0.89 mg soil sample spiked with 6000 ppm PET microplastics was measured to contain 4.98 µg of PET (5595 ppm, quantitation error: 6.8 %). Strikingly, PS nanoplastics (200 nm size) in mouse placentas were successfully identified and quantified, highlighting the method's ability to analyze biological tissue without tedious sample preparation. Overall, this study demonstrates the high potential of FI-MS for real-world sample analysis of MPs and NPs in environmental, biological, or consumer product samples.