1. Reliability Testing of Machine Learning Model Prediction Capability towards Unidentifiable Microplastic Spectral Data: Triple Battery and Colorant Investigation.
- Author
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Williams, Wesley A. and Aravamudhan, Shyam
- Subjects
ARTIFICIAL intelligence ,K-nearest neighbor classification ,COPPER phthalocyanine ,MICROPLASTICS ,ANALYTICAL chemistry - Abstract
Microplastics (MPs) are exudated fragments and fibers from environmental plastic refuse in the lower millimeter to micrometer range with some intentionally created particles and degraded exudates from anthropogenic sources. These particles are often hard to identify due to extensive weathering and material heterogeneity from additives. Leveraging the ability of machine learning (ML) models, which train on features from selected polymer classes, can aid in determining particle identity despite heterogeneity. Herein, a 1,800 spectral training dataset was employed for model training (900 from µ-FTIR and 900 from µ-Raman) using data from common MP polymers (synthetically or naturally derived) and plastics. A threefold battery; synthetic data (SD), mixed synthetic data (MSD), and real-world data from an FTIR Library of Plastic Particles sourced from the Environment (FLOPP-E) and a [Raman] Spectral Library of Plastic Particles aged in the Environment (SLOPP-E); was administered for reliability. Firstly, the SD test determined subspace k-nearest neighbors (SKNN) and wide neural network (WNN) as champions (µ-FTIR and µ-Raman, respectively) with an accuracy of, 99%/100% and 98%/100% (χ
2 = 31.99/69, p =.0024/ <.0001). Secondly, the MSD test served as a progenitor to the multi-class prediction from µ-Raman's SKNN showing consistency across 5 replicates (H =.25—6.59, p =.156—.993). And thirdly, the real-world test exhibited a loss in accuracy rate with only the champion, SKNN, retaining ~ 73% and ~ 49% of the correct predictions. Investigation into the probable causes of misprediction via colorant additives led to the discovery of white and blue as the most unpredictable across both databases. Lastly, an investigation of 2 samples revealed confounding colorant additives (SKNN's predictions) as copper phthalocyanine (C2. Blue Fiber) and a derivative from the family of diketo-pyrrolo-pyrroles (Polyester 12. Red Fiber). [ABSTRACT FROM AUTHOR]- Published
- 2025
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