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Signal Processing Methods to Interpret Polychlorinated Biphenyls in Airborne Samples
Journal article   Open access   Peer reviewed

Signal Processing Methods to Interpret Polychlorinated Biphenyls in Airborne Samples

Ryan A McCarthy, Ananya Sen Gupta, Bernice Kubicek, Andrew M Awad, Andres Martinez, Rachel F Marek and Keri C Hornbuckle
IEEE access, Vol.8, pp.147738-147755
2020
DOI: 10.1109/ACCESS.2020.3013108
PMCID: PMC7742762
PMID: 33335823
url
https://doi.org/10.1109/ACCESS.2020.3013108View
Published (Version of record) Open Access

Abstract

The main contribution of this interdisciplinary work is a robust computational framework to autonomously discover and quantify previously unknown associations between well-known (target) and potentially unknown (non-target) toxic industrial air pollutants. In this work, the variability of polychlorinated biphenyl (PCB) data is evaluated using a combination of statistical, signal processing, and graph-based informatics techniques to interpret the raw instrument signal from gas chromatography-mass spectrometry (GC/MS/MS) data sets. Specifically, minimum mean-squared techniques from the adaptive signal processing literature are extended to detect and separate coeluted (overlapped) peaks in the raw instrument signal. A graph-based visualization is provided which bridges two complementary approaches to quantitative pollution studies: (i) peak-cognizant target analysis (limits data analysis to few well-known compounds) and (ii) chemometric analysis (statistical large-scale data analysis) that is agnostic of specific compounds. Further, peak fitting techniques based on L2 error minimization are employed to autonomously calculate the amount of each PCB present with a normalized mean square error of -18.4851 dB. Graph-based visualization of associations between known and unknown compounds are developed through principal component analysis and both fuzzy c-means (FCM) and k-means clustering techniques are implemented and compared. The efficiency of these methods are compared using 150 air samples analyzed for individual PCBs with GC/MS/MS against traditional target-only techniques that perform analysis across only the known (target) PCBs. Parameter optimization techniques are employed to evaluate the relative contribution of PCB signals against ten potential source signals representing legacy signatures from historical manufacture of Aroclors and modern sources of PCBs produced as byproducts of pigment and polymer manufacturing. Aroclors 1232, 1254, 1016, and 1221 as well as non-Aroclor 3, 3', dichlorobiphenyl (PCB 11) were found in many of the samples as unique source signals that describe PCB mixtures in air samples collected from Chicago, IL.
Signal Processing PCBs Instruments Identifying sources Signal processing algorithms interpreting GC/MS/MS Compounds Chemicals Principal component analysis Load modeling ISRP Project 4 2020-2025 Analytical Core

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