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Quantitative analysis of multiple high-resolution mass spectrometry images using chemometric methods: Quantitation of chlordecone in mouse liver

Abstract

In this work, a chemometrics-based strategy is developed for quantitative mass spectrometry imaging (MSI). In this regard, quantification of chlordecone as a carcinogenic organochlorinated pesticide (C10Cll0O) in mouse liver using matrix-assisted laser desorption ionization MSI (MALDI-MSI) method is used as a case study. The MSI data sets were corresponded to 1, 5 and 10 days of mouse exposure to the standard of chlordecone in quantity range of 0 to 450 µg/g. Binning approach in m/z direction is used to group high resolution m/z values and to reduce the big data size. To consider the effect of bin size on the quality of results, three different bin sizes of 0.25, 0.5 and 1.0 were chosen. Afterwards, three-way MSI data arrays (two spatial and one m/z dimensions) for seven standards and four unknown samples were column-wise augmented with m/z values as common mode. Then, these data sets were analyzed using multivariate curve resolution-alternating least squares (MCR-ALS) using proper constraints. The resolved mass spectra were used for identification of chlordecone in the presence of complex background and interferences. Additionally, the augmented spatial profiles were post-processed and 2D images for each component were obtained in calibration and unknown samples. The sum of these profiles was utilized to set the calibration curve and to obtain analytical figures of merit (AFOMs). Inspection of the results showed that the lower bin size (i.e., 0.25) provides more accurate results. Finally, the obtained results by MCR for three data sets were compared with those of gas chromatography-mass spectrometry (GC-MS) and MALDI-MSI. The results showed that MCR-assisted method gives chlordecone amount higher than MALDI-MSI and lower than GC-MS. It is concluded that combination of chemometric methods with MSI can be considered as an alternative way for MSI quantification.

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Supplementary files

Publication details

The article was received on 20 Dec 2017, accepted on 29 Mar 2018 and first published on 05 Apr 2018


Article type: Paper
DOI: 10.1039/C7AN02059G
Citation: Analyst, 2018, Accepted Manuscript
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    Quantitative analysis of multiple high-resolution mass spectrometry images using chemometric methods: Quantitation of chlordecone in mouse liver

    S. Mohammadi and H. Parastar, Analyst, 2018, Accepted Manuscript , DOI: 10.1039/C7AN02059G

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