Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Aug;410(21):5131-5141.
doi: 10.1007/s00216-018-1156-x. Epub 2018 Jul 6.

Reference database design for the automated analysis of microplastic samples based on Fourier transform infrared (FTIR) spectroscopy

Sebastian Primpke  1 , Marisa Wirth  2   3 , Claudia Lorenz  2 , Gunnar Gerdts  2
Affiliations

Reference database design for the automated analysis of microplastic samples based on Fourier transform infrared (FTIR) spectroscopy

Sebastian Primpke et al. Anal Bioanal Chem. 2018 Aug.

Abstract

The identification of microplastics becomes increasingly challenging with decreasing particle size and increasing sample heterogeneity. The analysis of microplastic samples by Fourier transform infrared (FTIR) spectroscopy is a versatile, bias-free tool to succeed at this task. In this study, we provide an adaptable reference database, which can be applied to single-particle identification as well as methods like chemical imaging based on FTIR microscopy. The large datasets generated by chemical imaging can be further investigated by automated analysis, which does, however, require a carefully designed database. The novel database design is based on the hierarchical cluster analysis of reference spectra in the spectral range from 3600 to 1250 cm-1. The hereby generated database entries were optimized for the automated analysis software with defined reference datasets. The design was further tested for its customizability with additional entries. The final reference database was extensively tested on reference datasets and environmental samples. Data quality by means of correct particle identification and depiction significantly increased compared to that of previous databases, proving the applicability of the concept and highlighting the importance of this work. Our novel database provides a reference point for data comparison with future and previous microplastic studies that are based on different databases. Graphical abstract ᅟ.

Keywords: Database; FTIR; Imaging; Infrared; Microplastics; Spectroscopy.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Graphical abstract
Graphical abstract
ᅟ
Fig. 1
Fig. 1
Dendrogram of manually generated clusters. For lucidity, the spectra were grouped and the number of contained spectra written in brackets behind the cluster name. All merged clusters (see text for details) were connected by green lines; for all later excluded clusters, the lines are marked red (reduction of clusters) and orange (cluster categories)
Fig. 2
Fig. 2
Image analysis pictures of single particles with different assigned database entries
Fig. 3
Fig. 3
Photograph (a), unclosed image (b), and closed image (c) of a piece of cellulose foil. Closed image (d) of the same particle when silica gel is present in the adaptable database design
Fig. 4
Fig. 4
Polymer-type-dependent false color image of the sample RefEnv1 after automated analysis with the adaptable database design
Fig. 5
Fig. 5
Polymer-type-dependent false color image of the sample RevEnv2 after automated analysis with the adaptable database design
Fig. 6
Fig. 6
Size distribution and polymer composition for plastic particles derived via automated analysis for the sample RevEnv2. The region for particles with a size > 50 μm was highlighted for a better overview
See this image and copyright information in PMC

References

    1. Thompson RC, Olsen Y, Mitchell RP, Davis A, Rowland SJ, John AWG, et al. Lost at sea: where is all the plastic? Science. 2004;304(5672):838. doi: 10.1126/science.1094559. - DOI - PubMed
    1. Ivleva NP, Wiesheu AC, Niessner R. Microplastic in aquatic ecosystems. Angew Chem Int Ed. 2017;56(7):1720–1739. doi: 10.1002/anie.201606957. - DOI - PubMed
    1. Andrady AL. The plastic in microplastics: a review. Mar Pollut Bull. 2017;119:12–22. doi: 10.1016/j.marpolbul.2017.01.082. - DOI - PubMed
    1. Hidalgo-Ruz V, Gutow L, Thompson RC, Thiel M. Microplastics in the marine environment: a review of the methods used for identification and quantification. Environ Sci Technol. 2012;46(6):3060–3075. doi: 10.1021/es2031505. - DOI - PubMed
    1. GESAMP. Sources, fate and effects of microplastics in the marine environment: a global assessment. Rep Stud GESAMP. 2015;90:1–98.