Pei Yuexin, Pei Xinlong, Shang Ruichao, Wang Zehui, Liang Gang, Li Long, Yue Ying, Zhu Hong, Gong Wenwen
College of Bioscience and Resource Environment, Beijing University of Agriculture, Beijing, 102206, People's Republic of China.
Institute of Quality Standard and Testing Technology, BAAFS (Beijing Academy of Agriculture and Forestry Sciences), Beijing, 100097, People's Republic of China.
Anal Bioanal Chem. 2025 Aug 8. doi: 10.1007/s00216-025-06046-0.
The widely accepted application of polylactic acid (PLA) films as agricultural mulch films has led to the accumulation of microplastics (MPs) in soil ecosystems, causing severe white pollution. Developing a convenient method to detect PLA in the environment is essential for pollution control. In this study, single-atom nickel-doped nitrogen on carbon nanosheets (Ni-N-C) combined with gold-palladium nanoparticles (AuPdNPs) enabled highly sensitive lactic acid detection. Through oxidation catalyzed by the single-atom metal, the detection range for lactic acid was 50 μmol·L⁻ to 50 mmol·L⁻, with a detection limit of 10 μmol·L⁻. This approach indirectly quantified PLA in MPs via lactic acid detection on Ni-N-C + AuPdNPs. This is the first electrochemical method to indirectly determine depolymerized polylactic acid for environmental PLA quantification. The detection current showed minimal fluctuation over 7 days and remained unaffected by common soil interferents. It demonstrates strong applicability in real environments by indirectly assessing MP residues through their depolymerization products, avoiding complex separation processes. High PLA recovery rates in water and soil highlight its potential for environmental monitoring. A stable electrochemical detection of microplastic monomers was provided for such detection approaches.
聚乳酸（PLA）薄膜作为农用薄膜被广泛应用，导致土壤生态系统中微塑料（MPs）积累，造成严重的白色污染。开发一种便捷的环境中PLA检测方法对于污染控制至关重要。在本研究中，碳纳米片上的单原子镍掺杂氮（Ni-N-C）与金钯纳米颗粒（AuPdNPs）相结合，实现了对乳酸的高灵敏度检测。通过单原子金属催化氧化，乳酸的检测范围为50 μmol·L⁻至50 mmol·L⁻，检测限为10 μmol·L⁻。该方法通过在Ni-N-C + AuPdNPs上检测乳酸间接定量MPs中的PLA。这是第一种间接测定解聚聚乳酸以进行环境中PLA定量的电化学方法。检测电流在7天内波动极小，且不受常见土壤干扰物的影响。通过间接评估MPs的解聚产物来评估其残留量，避免了复杂的分离过程，证明了其在实际环境中的强大适用性。水和土壤中PLA的高回收率突出了其在环境监测中的潜力。为这种检测方法提供了一种稳定的微塑料单体电化学检测方法。
