Tang R, Gong C, Liu Y, Zhong H, Wang Y, Zhou H.

Front Immunol

PMID:PMC13082970

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Elmaidomy AH, Mohamed EM, El-Dien RTM, Abou-Zied HA, Mostafa AA, Taha RH, El-Badry MA, Abdelmohsen UR, Youssif KA.

Sci Rep

PMID:42010347

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He Z, Zhang Q, Xu X, Yang Z, Su W, Zhou Z, Liu S, Wang N, Yue L.

Anal Chem

PMID:42007547

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Electrospray ionization (ESI) is one of the most widely used ionization methods in commercial mass spectrometry. However, it is challenging to effectively ionize most nonpolar plastics. In this study, a low-cost, rapid, free of complex sample preparation, and capable of generating easily interpretable characteristic peaks method for MP identification was developed. It integrates cheap pyrolysis modules with conventional electrospray ionization mass spectrometry (PESI-MS) and operates with a minimal sample input of μm-scale in size and μg-scale in mass. It presents a limit of detection (LOD) of 0.1 μg and achieves a linear quantitative range of 0.2-1 μg with a coefficient of determination ( R 2 ) of 0.99, supporting accurate quantitative analysis of target MPs. Within 2.4 s, the polymer vapor generated during atmospheric pyrolysis at an optimal temperature of 400 °C was effectively ionized to provide characteristic backbone information. The method was initially applied to representative MPs, including polyolefins (polyethylene PE, polypropylene PP), polyacrylate (poly(methyl methacrylate) PMMA), polyesters (polyethylene terephthalate PET, polylactide PLA), nylon (polyamide 6, PA6), and polyformaldehyde (POM). Principal component analysis (PCA) of the PESI-MS data revealed distinct spectral features for each MP type. In addition, Pearson product-moment correlation coefficient (PPMC) analysis elucidates both similarities and differences among the polymers and enables precise identification of MPs. Finally, the combined application of PESI-MS and PPMC analysis was used to comprehensively analyze nonplastic, plastic, and real-life samples, thereby validating the effectiveness of this approach in identifying environmental MPs.

Krishna R, Millard G, Bradshaw R, Cole LM, Francese S.

Anal Chem

PMID:42009376

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Since its inception in 2004, Desorption Electrospray Ionization Mass Spectrometry (DESI MS) has seen a significant increase in its application to the pharmaceutical and clinical setting, supported by a steady improvement of the sensitivity, mass accuracy, mass resolution, spatial resolution and usability, as well as by the advantages offered by its ambient nature. However, in comparison to the rapid growth for tissue imaging, the uptake of DESI-MSI in fingerprint imaging has not grown a substantial body of knowledge, compared to MALDI-MSI. In this work, we set off to dissect the application of DESI-MSI to fingerprint imaging to explore both the advantages and the potential challenges that might have slowed the uptake, taking stock from our previous work and that of others in this area. During this endeavor we have highlighted advantages but also discovered that, under a range of optimized operating conditions, fingerprint imaging by DESI-MSI is affected by a delocalization phenomenon which we termed "the bleeding effect". This phenomenon has been shown to be specific to fingerprints, as sample type, as opposed to biological tissues, and may be one of the contributing factors to a seemingly slower uptake of this technique in molecular fingerprinting. Therefore, a description of the observed effect, how to minimize it, and its implications in operational work are discussed.

Imran S, Patel M, Noroozifar M, Kerman K.

RSC Med Chem

PMID:PMC13086042

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