Abstract
In recent years, many studies on the analysis of microplastics (MP) in environmental samples have been published. These studies are hardly comparable due to different sampling, sample preparation, as well as identification and quantification techniques. Here, MP identification is one of the crucial pitfalls. Visual identification approaches using morphological criteria alone often lead to significant errors, being especially true for MP fibers. Reliable, chemical structure-based identification methods are indispensable. In this context, the frequently used vibrational spectroscopic techniques but also thermoanalytical methods are established. However, no critical comparison of these fundamentally different approaches has ever been carried out with regard to analyzing MP in environmental samples. In this blind study, we investigated 27 single MP particles and fibers of unknown material isolated from river sediments. Successively micro-attenuated total reflection Fourier transform infrared spectroscopy (μ-ATR-FTIR) and pyrolysis gas chromatography-mass spectrometry (py-GCMS) in combination with thermochemolysis were applied. Both methods differentiated between plastic vs. non-plastic in the same way in 26 cases, with 19 particles and fibers (22 after re-evaluation) identified as the same polymer type. To illustrate the different approaches and emphasize the complementarity of their information content, we exemplarily provide a detailed comparison of four particles and three fibers and a critical discussion of advantages and disadvantages of both methods.
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Andrady AL. Microplastics in the marine environment. Mar Pollut Bull. 2011;62:1596–605. https://doi.org/10.1016/j.marpolbul.2011.05.030.
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;46:3060–75. https://doi.org/10.1021/es2031505.
Ivleva NP, Wiesheu AC, Niessner R. Microplastic in aquatic ecosystems. Angew Chem Int Ed. 2017;56:1720–39. https://doi.org/10.1002/anie.201606957.
Eriksen M, Mason S, Wilson S, Box C, Zellers A, Edwards W, et al. Microplastic pollution in the surface waters of the Laurentian Great Lakes. Mar Pollut Bull. 2013;77:177–82. https://doi.org/10.1016/j.marpolbul.2013.10.007.
Song YK, Hong SH, Jang M, Han GM, Rani M, Lee J, et al. A comparison of microscopic and spectroscopic identification methods for analysis of microplastics in environmental samples. Mar Pollut Bull. 2015;93:202–9. https://doi.org/10.1016/j.marpolbul.2015.01.015.
Lenz R, Enders K, Stedmon CA, Mackenzie DMA, Nielsen TG. A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement. Mar Pollut Bull. 2015;100:82–91. https://doi.org/10.1016/j.marpolbul.2015.09.026.
Remy F, Collard F, Gilbert B, Compère P, Eppe G, Lepoint G. When microplastic is not plastic: the ingestion of artificial cellulose fibers by macrofauna living in Seagrass Macrophytodetritus. Environ Sci Technol. 2015;49:11158–66. https://doi.org/10.1021/acs.est.5b02005.
Rocha-Santos T, Duarte AC. A critical overview of the analytical approaches to the occurrence, the fate and the behavior of microplastics in the environment. Trends Anal Chem. 2015;65:47–53. https://doi.org/10.1016/j.trac.2014.10.011.
Dris R, Imhof H, Sanchez W, Gasperi J, Galgani F, Tassin B, et al. Beyond the ocean: contamination of freshwater ecosystems with (micro-)plastic particles. Environ Chem. 2015;12:539. https://doi.org/10.1071/EN14172.
Käppler A, Fischer D, Oberbeckmann S, Schernewski G, Labrenz M, Eichhorn KJ, et al. Analysis of environmental microplastics by vibrational microspectroscopy: FTIR, Raman or both? Anal Bioanal Chem. 2016;408:8377–91. https://doi.org/10.1007/s00216-016-9956-3.
Mani T, Hauk A, Walter U, Burkhardt-Holm P. Microplastics profile along the Rhine River. Sci Rep. 2015;5:1–7. https://doi.org/10.1038/srep17988.
Klein S, Worch E, Knepper TP. Occurrence and spatial distribution of microplastics in river shore sediments of the Rhine-Main Area in Germany. Environ Sci Technol. 2015;49:6070–6. https://doi.org/10.1021/acs.est.5b00492.
Imhof HK, Sigl R, Brauer E, Feyl S, Giesemann P, Klink S, et al. Spatial and temporal variation of macro-, meso- and microplastic abundance on a remote coral island of the Maldives, Indian Ocean. Mar Pollut Bull. 2017;116:340–7. https://doi.org/10.1016/j.marpolbul.2017.01.010.
Vianello A, Boldrin A, Guerriero P, Moschino V, Rella R, Sturaro A, et al. Microplastic particles in sediments of Lagoon of Venice, Italy: first observations on occurrence, spatial patterns and identification. Estuar Coast Shelf Sci. 2013;130:54–61. https://doi.org/10.1016/j.ecss.2013.03.022.
Harrison JP, Ojeda JJ, Romero-González ME. The applicability of reflectance micro-Fourier-transform infrared spectroscopy for the detection of synthetic microplastics in marine sediments. Sci Total Environ. 2012;416:455–63. https://doi.org/10.1016/j.scitotenv.2011.11.078.
Tagg AS, Sapp M, Harrison JP, Ojeda JJ. Identification and quantification of microplastics in wastewater using focal plane array-based reflectance micro-FT-IR imaging. Anal Chem. 2015;87:6032–40. https://doi.org/10.1021/acs.analchem.5b00495.
Ter Halle A, Jeanneau L, Martignac M, Jardé E, Pedrono B, Brach L, et al. Nanoplastic in the North Atlantic subtropical gyre. Environ Sci Technol. 2017;51:13689–97. https://doi.org/10.1021/acs.est.7b03667.
Frias JPGL, Otero V, Sobral P. Evidence of microplastics in samples of zooplankton from Portuguese coastal waters. Mar Environ Res. 2014;95:89–95. https://doi.org/10.1016/j.marenvres.2014.01.001.
Löder MGJ, Kuczera M, Mintenig S, Lorenz C, Gerdts G. Focal plane array detector-based micro-Fourier-transform infrared imaging for the analysis of microplastics in environmental samples. Environ Chem. 2015;12:563–81. https://doi.org/10.1071/EN14205.
Rummel CD, Löder MGJ, Fricke NF, Lang T, Griebeler EM, Janke M, et al. Plastic ingestion by pelagic and demersal fish from the North Sea and Baltic Sea. Mar Pollut Bull. 2016;102:134–41. https://doi.org/10.1016/j.marpolbul.2015.11.043.
Mintenig SM, Int-Veen I, Löder MGJ, Primpke S, Gerdts G. Identification of microplastic in effluents of waste water treatment plants using focal plane array-based micro-Fourier-transform infrared imaging. Water Res. 2017;108:365–72. https://doi.org/10.1016/j.watres.2016.11.015.
Bergmann M, Wirzberger V, Krumpen T, Lorenz C, Primpke S, Tekman MB, et al. High quantities of microplastic in Arctic deep-sea sediments from the HAUSGARTEN observatory. Environ Sci Technol. 2017;51:11000–10. https://doi.org/10.1021/acs.est.7b03331.
Matsuguma Y, Takada H, Kumata H, Kanke H, Sakurai S, Suzuki T, et al. Microplastics in sediment cores from Asia and Africa as indicators of temporal trends in plastic pollution. Arch Environ Contam Toxicol. 2017;73:230–9. https://doi.org/10.1007/s00244-017-0414-9.
Primpke S, Lorenz C, Rascher-Friesenhausen R, Gerdts G. An automated approach for microplastics analysis using focal plane array (FPA) FTIR microscopy and image analysis. Anal Methods. 2017;9:1499–511. https://doi.org/10.1039/c6ay02476a.
Majewsky M, Bitter H, Eiche E, Horn H. Determination of microplastic polyethylene (PE) and polypropylene (PP) in environmental samples using thermal analysis (TGA-DSC). Sci Total Environ. 2016;568:507–11. https://doi.org/10.1016/j.scitotenv.2016.06.017.
Dümichen E, Barthel A-K, Braun U, Bannick CG, Brand K, Jekel M, et al. Analysis of polyethylene microplastics in environmental samples, using a thermal decomposition method. Water Res. 2015;85:451–7. https://doi.org/10.1016/j.watres.2015.09.002.
Dümichen E, Eisentraut P, Bannick CG, Barthel A-K, Senz R, Braun U. Fast identification of microplastics in complex environmental samples by a thermal degradation method. Chemosphere. 2017;174:572–84. https://doi.org/10.1016/j.chemosphere.2017.02.010.
Challinor JM. Review: the development and applications of thermally assisted hydrolysis and methylation reactions. J Anal Appl Pyrolysis. 2001;61:3–34.
Challinor JM. A pyrolysis-derivatisation-gas chromatography technique for the structural elucidation of some synthetic polymers. J Anal Appl Pyrolysis. 1989;16:323–33.
Shadkami F, Helleur R. Recent applications in analytical thermochemolysis. J Anal Appl Pyrolysis. 2010;89:2–16. https://doi.org/10.1016/j.jaap.2010.05.007.
Antić VV, Antić MP, Kronimus A, Oing K, Schwarzbauer J. Quantitative determination of poly(vinylpyrrolidone) by continuous-flow off-line pyrolysis-GC/MS. J Anal Appl Pyrolysis. 2011;90:93–9. https://doi.org/10.1016/j.jaap.2010.10.011.
de Leeuw JW, de Leer EWB, Sinninghe Damsté JS, Schuyl PJW. Screening of anthropogenic compounds in polluted sediments and soils by flash evaporation/pyrolysis gas chromatography-mass spectrometry. Anal Chem. 1986;58:1852–7.
Fabbri D, Tartari D, Trombini C. Analysis of poly(vinyl chloride) and other polymers in sediments and suspended matter of a coastal lagoon by pyrolysis-gas chromatography-mass spectrometry. Anal Chim Acta. 2000;413:3–11. https://doi.org/10.1016/S0003-2670(00)00766-2.
Fabbri D. Use of pyrolysis-gas chromatography/mass spectrometry to study environmental pollution caused by synthetic polymers: a case study: the Ravenna lagoon. J Anal Appl Pyrolysis. 2001;58–59:361–70. https://doi.org/10.1016/S0165-2370(00)00170-4.
Fabbri D, Trombini C, Vassura I. Analysis of polystyrene in polluted sediments by pyrolysis-gas chromatography-mass spectrometry. J Chromatogr Sci. 1998;36:600–4.
Nuelle M-T, Dekiff JH, Remy D, Fries E. A new analytical approach for monitoring microplastics in marine sediments. Environ Pollut. 2014;184:161–9. https://doi.org/10.1016/j.envpol.2013.07.027.
Dekiff JH, Remy D, Klasmeier J, Fries E. Occurrence and spatial distribution of microplastics in sediments from Norderney. Environ Pollut. 2014;186:248–56. https://doi.org/10.1016/j.envpol.2013.11.019.
Fries E, Dekiff JH, Willmeyer J, Nuelle M-T, Ebert M, Remy D. Identification of polymer types and additives in marine microplastic particles using pyrolysis-GC/MS and scanning electron microscopy. Environ Sci Process Impacts. 2013;15:1949–56. https://doi.org/10.1039/c3em00214d.
Fischer M, Scholz-Böttcher BM. Simultaneous trace identification and quantification of common types of microplastics in environmental samples by pyrolysis-gas chromatography−mass spectrometry. Environ Sci Technol. 2017;51:5052–60. https://doi.org/10.1021/acs.est.6b06362.
Elert AM, Becker R, Duemichen E, Eisentraut P, Falkenhagen J, Sturm H, et al. Comparison of different methods for MP detection: what can we learn from them, and why asking the right question before measurements matters? Environ Pollut. 2017;231:1256–64. https://doi.org/10.1016/j.envpol.2017.08.074.
Imhof HK, Schmid J, Niessner R, Ivleva NP, Laforsch C. A novel, highly efficient method for the separation and quantification of plastic particles in sediments of aquatic environments. Limnol Oceanogr Methods. 2012;10:524–37. https://doi.org/10.4319/lom.2012.10.524.
Tsuge S, Ohtani H, Watanabe C. Pyrolysis—GC/MS data book of synthetic polymers. 1st ed. Oxford: Elsevier B.V.; 2011.
Mandelkern L, Alamo RG. Polyethylene, linear high-density. In: Mark JE, editor. Polymer data handbook. Oxford: Oxford University Press; 1991. p. 493–507.
Beyler CL, Hirschler MM. Thermal decomposition of polymers. In: Beyler CL, Custer RLP, Walton WD, John MJW, Drysdale D, John RJH, et al., editors. SFPE handbook of fire protection engineering, 3rd ed. National Fire Protection Association; 2005. p. 110–31.
Narita S, Ichinohe S, Enomoto S. Infrared spectrum of polyvinyl chloride. J Polym Sci. 1959;37:273–80.
Stromberg RR, Straus S, Achhammer BG. Infrared spectra of thermally degraded poly(vinyl chloride). J Res Natl Bur Stand (1934). 1958;60:147–52. https://doi.org/10.6028/jres.060.018.
Tabb DL, Koenig JL. Fourier transform infrared study of plasticized and unplasticized poly(vinyl chloride). Macromolecules. 1975;8:929–34. https://doi.org/10.1021/ma60048a043.
González N, Fernández-Berridi MJ. Application of Fourier transform infrared spectroscopy in the study of interactions between PVC and plasticizers: PVC/plasticizer compatibility versus chemical structure of plasticizer. J Appl Polym Sci. 2006;101:1731–7. https://doi.org/10.1002/app.23381.
Ploeger R, Scalarone D, Chiantore O. The characterization of commercial artists’ alkyd paints. J Cult Herit. 2008;9:412–9. https://doi.org/10.1016/j.culher.2008.01.007.
Duce C, Della Porta V, Tiné MR, Spepi A, Ghezzi L, Colombini MP, et al. FTIR study of ageing of fast drying oil colour (FDOC) alkyd paint replicas. Spectrochim Acta A Mol Biomol Spectrosc. 2014;130:214–21. https://doi.org/10.1016/j.saa.2014.03.123.
Gunasekaran S, Anbalagan G, Pandi S. Raman and infrared spectra of carbonates of calcite structure. J Raman Spectrosc. 2006;37:892–9. https://doi.org/10.1002/jrs.1518.
Ziêba-Palus J, Milczarek JM, Koscielniak P. Application of infrared spectroscopy and pyrolysis-gas chromatography – mass spectrometry to the analysis of automobile paint samples. Chem Anal. 2008;53:109–21.
Hummel DO, Scholl F. Atlas der Polymer- und Kunststoffanalyse, Band 2 Kunststoff, Fasern, Kautschuk, Harze, Ausgangs- und Hilfsstoffe, Abbauprodukte - Teil b/I. 2. VCH, Weinheim; 1988.
Hummel DO, Scholl F. Atlas of polymer and plastics analysis, volume 2 plastics, fibres, rubbers, resins; starting and auxiliary materials, degradation products, part a/I. 2. VCH, Weinheim; 1984.
Huang CK, Kerr PF. Infrared study of the carbonate minerals. Am Mineral. 1960;45:311–24.
Mitić Ž, Stolić A, Stojanović S, Najman S, Ignjatović N, Nikolić G, et al. Instrumental methods and techniques for structural and physicochemical characterization of biomaterials and bone tissue: a review. Mater Sci Eng C. 2017;79:930–49. https://doi.org/10.1016/j.msec.2017.05.127.
Learner T. The analysis of synthetic paints by pyrolysis-gas chromatography-mass spectrometry (PyGCMS). Stud Conserv. 2001;46:225–41.
Challinor JM. Structure determination of alkyd resins by simultaneous pyrolysis methylation. J Anal Appl Pyrolysis. 1991;18:233–44.
Wei S, Pintus V, Schreiner M. A comparison study of alkyd resin used in art works by Py-GC/MS and GC/MS: the influence of aging. J Anal Appl Pyrolysis. 2013;104:441–7. https://doi.org/10.1016/j.jaap.2013.05.028.
Koopmans RJ, van der Linden R, Vansant EF. Quantitative determination of the vinylacetate content in ethylene vinyl-acetate copolymers—a critical review. Polym Eng Sci. 1982;22:878–82.
Rimez B, Rahier H, Van Assche G, Artoos T, Biesemans M, Van Mele B. The thermal degradation of poly(vinyl acetate) and poly(ethylene-co-vinyl acetate), part I: experimental study of the degradation mechanism. Polym Degrad Stab. 2008;93:800–10. https://doi.org/10.1016/j.polymdegradstab.2008.01.010.
Comnea-Stancu IR, Wieland K, Ramer G, Schwaighofer A, Lendl B. On the identification of rayon/viscose as a major fraction of microplastics in the marine environment: discrimination between natural and manmade cellulosic fibers using Fourier transform infrared spectroscopy. Appl Spectrosc. 2017;71:939–50. https://doi.org/10.1177/0003702816660725.
Baran A, Fiedler A, Schulz H, Baranska M. In situ Raman and IR spectroscopic analysis of indigo dye. Anal Methods. 2010;2:1372–6. https://doi.org/10.1039/c0ay00311e.
Ibrahim M, El-Nahass MM, Kamel MA, El-Barbary AA, Wagner BD, El-Mansy MAM. On the spectroscopic analyses of thioindigo dye. Spectrochim Acta - Part A Mol Biomol Spectrosc. 2013;113:332–6. https://doi.org/10.1016/j.saa.2013.05.014.
Fabbri D, Helleur R. Characterization of the tetramethylammonium hydroxide thermochemolysis products of carbohydrates. J Anal Appl Pyrolysis. 1999;49:277–93. https://doi.org/10.1016/S0165-2370(98)00085-0.
Schwarzinger C, Tanczos I, Schmidt H. Levoglucosan, cellobiose and their acetates as model compounds for the thermally assisted hydrolysis and methylation of cellulose and cellulose acetate. J Anal Appl Pyrolysis. 2002;62:179–96. https://doi.org/10.1016/S0165-2370(01)00114-0.
Acknowledgments
This work was part of the Leibniz Competition project “Microplastics as vector for microbial populations in the ecosystem of the Baltic Sea (MikrOMIK),” funded by the German Leibniz Association (grant number SAW-2014-IOW-2). Parts of this study were funded by the German Federal Ministry of Education and Research (BMBF 03F0734D) in the joint research project BASEMAN (JPI-Oceans microplastics projects). Furthermore, Andrea Käppler is thankful for financial support by the BONUS MICROPOLL project funded jointly by the EU and BMBF (03F0775A).
The authors want to thank Rica Wegner, Nicole Stollberg, and Oliver Biniasch (all formerly IOW) for the extraction and isolation of the particles and fibers. The technical assistance of Oliver Voigt (IPF) during ATR-FTIR measurements is also acknowledged.
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Käppler, A., Fischer, M., Scholz-Böttcher, B.M. et al. Comparison of μ-ATR-FTIR spectroscopy and py-GCMS as identification tools for microplastic particles and fibers isolated from river sediments. Anal Bioanal Chem 410, 5313–5327 (2018). https://doi.org/10.1007/s00216-018-1185-5
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DOI: https://doi.org/10.1007/s00216-018-1185-5