Identification and quantification of microplastics in omega-3 products using micro Fourier transform infrared spectroscopy

Given the prevalence of MP contamination in marine environments and the potential for ingestion, this study focused on detecting MPs in widely consumed omega-3 supplements. We developed and validated a testing method for analyzing microplastics (MPs) in omega-3 dietary supplements using micro-Fourier-transform infrared spectroscopy (μ-FT-IR). For sample preparation, 30% H₂O₂ pretreatment and 20 μm stainless-steel filtration were adopted to digest omega-3 samples. A total of 88 omega-3 products were collected and examined, including animal- and plant-origin omega-3 with different packaging materials. Recovery test using reference MP materials was conducted to enhance the reliability of the method. As a result, the recovery was more than 70.4%, and relative standard deviation was below 36.9% in three laboratories. MPs (>20 μm) were detected in all the samples. The number of MPs were 9.5 ± 5.3 particles/g and 16.3 ± 8.1 particles/serving size. The developed method can be applied to MP analysis of omega-3 supplements.