Microplastic analysis

Microplastics (MPs) are an emerging class of environmental pollutants, typically defined as plastic particles with sizes ranging from approximately 1 μm to 5 mm. Plastic waste entering natural environments undergoes fragmentation through physical abrasion, chemical degradation, and biological processes, ultimately forming microplastics. In addition to secondary microplastics derived from larger debris, primary microplastics—such as microspheres and synthetic fibers released from cosmetics, cleaning products, and textiles—are also significant contributors to environmental contamination.

Research on microplastics primarily focuses on environmental impacts and potential human health risks. Major research areas include pollution characteristics and source apportionment, degradation behavior and surface property evolution, environmental transport and fate modeling, bioaccumulation and ecotoxicological effects, and interactions between microplastics and coexisting contaminants. Qualitative and quantitative analysis of microplastics, along with the identification of polymer types, additives, and adsorbed pollutants, is therefore a fundamental requirement for microplastics research and regulatory assessment. Matexcel provides comprehensive microplastics compositional analysis services to support environmental monitoring, risk evaluation, and academic or industrial research.

Our analytical workflows integrate polymer identification, particle counting and sizing, mass concentration determination, and surface chemical characterization. Methods are selected based on particle size range, sample matrix, and study objectives, and are implemented in alignment with commonly adopted ASTM and ISO standards and international best practices.

Fourier Transform Infrared Spectroscopy (FTIR), including micro-FTIR imaging, is widely used for rapid polymer identification of microplastics collected on filters. This technique enables qualitative characterization of organic polymers and selected inorganic components, even for very small particles, through comparison with established spectral libraries. FTIR-based identification is commonly aligned with ASTM E1252 and ISO 10640, and is consistent with the guidance provided in ISO/TR 21960 for environmental plastics analysis.

Laser Direct Infrared (LDIR) spectroscopy is applied for automated particle counting, sizing, and polymer identification of microplastics. This technique enables high-throughput analysis of particles in the size range of approximately 20–500 μm and supports identification of more than 40 common polymer types. LDIR analysis provides outputs including particle counts by polymer type (e.g., polypropylene particle count), particle size distribution, and morphological information. Sample preparation typically involves flotation-based separation, chemical digestion to remove organic matter, and membrane filtration prior to spectroscopic measurement. LDIR-based workflows are increasingly adopted for standardized microplastics monitoring due to their speed, reproducibility, and quantitative capabilities.

Pyrolysis Gas Chromatography–Mass Spectrometry (Py-GC/MS) is employed for quantitative determination of microplastics based on mass concentration. This method is suitable for micro- to nano-scale plastic particles across the full-size range and enables identification and quantification of approximately 13 common polymer types. Following digestion and extraction steps to remove matrix interferences, polymer-specific pyrolysis products are analyzed by GC-MS, allowing accurate determination of polymer mass concentrations. Results are reported as concentrations (for example, polypropylene at x µg/kg or µg/L), making Py-GC/MS particularly suitable for exposure assessment and mass-balance studies. Analytical principles are consistent with ASTM D6370 and related thermal decomposition and GC-MS methodologies.

Other information such as Elemental and inorganic additive characterization can be performed using Energy-Dispersive X-ray Fluorescence Spectroscopy (EDXRF), which identifies and quantifies elements based on characteristic fluorescent X-ray emissions. This technique is useful for detecting fillers, pigments, and metal-containing additives associated with microplastics and is commonly aligned with ASTM E1621 and ISO 11885 standards. Thermal characterization of microplastics is conducted using Differential Scanning Calorimetry (DSC), which measures heat flow associated with phase transitions under controlled temperature programs. DSC data support polymer identification, crystallinity assessment, and component ratio estimation in mixed plastic samples, and are generated in accordance with ASTM D3418 and ISO 11357 series standards.

Particle-level size, shape, and number concentration analysis can also be performed using dynamic particle image analysis. This technique captures real-time images of particles suspended in liquid samples and rapidly provides statistically robust data on particle size distribution and morphology, supporting studies on environmental transport and exposure. Measurements are consistent with ISO 13322-2 and related image-based particle analysis standards.

Sample Requirements

Generally, a minimum sample volume of 500 mL per sample is recommended to ensure representativeness, with an absolute minimum of 1-100 mL acceptable in some limited cases (biological samples). Samples should be shipped at ambient temperature or dry ice conditions for biological samples using clean glass bottles. If plastic containers are unavoidable, the use of at least three field blanks is strongly recommended to control for potential contamination.

If you have any questions regarding microplastics testing methods, specifications, or sample preparation, please contact us to discuss a customized analytical solution tailored to your project requirements.

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