High-throughput detection and polymer profiling of microplastics in carbonated soft drinks using laser direct infrared (LDIR) spectroscopy across polyethylene terephthalate and aluminium packaging.

Microplastic (MP) contamination in beverages has emerged as a growing environmental and public health concern. In this study, Laser Direct Infrared (LDIR) spectroscopy was employed for the rapid detection, quantification, and polymer characterization of MPs in commercially available carbonated soft drinks packaged in polyethylene terephthalate (PET) bottles and aluminium cans in Malaysia. Triplicate samples from four major beverage brands were analyzed. MPs were detected in all samples, with concentrations ranging from 152 ± 110 to 330 ± 404 MPs/L in canned beverages and from 79 ± 17 to 727 ± 244 MPs/L in PET-packaged beverages. Overall, PET bottles exhibited higher MP concentrations than aluminium cans. Polymer analysis identified PET, polyvinyl chloride (PVC), polyamide (PA), polyurethane (PU), and polytetrafluoroethylene (PTFE) in these samples. Most detected particles were smaller than 50 μm. These findings demonstrate the suitability of LDIR spectroscopy as a rapid, automated, and high-throughput approach for comprehensive MP analysis in carbonated beverages.