Electronic Supplementary Material (ESI) for Analytical Methods. This journal is © The Royal Society of Chemistry 2021 Supplementary information Microplastic extraction from sediments established? – A critical evaluation from a trace recovery experiment with a custom-made density separator Maurits Halbach*, Christin Baensch, Sonka Dirksen and Barbara Scholz-Böttcher Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, P.O. Box 2503, D-26111 Oldenburg, Germany. Supplement content: 6 pages (cover page included), 8 tables, 3 figure Table S1 (page S-2) Grain size distribution of quartz sand Table S2 (page S-2) Spiked polymer masses in µg. Table S3 (page S-2) Spiked number of polymer particles. Table S4 (page S-4) Polymer specifications. Table S5 (page S-4) Injection Standards. Table S6 (page S-4) Conditions for Pyrolysis-GCMS/Thermochemolysis measurements. Table S7 (page S-5) Overview of different measurements sequences and accompanied calibrations. Table S8 (page S-5) List of polymers and their respective specific indicator ions. Table S9 (page S-6) Comparable information on recovery replicates and blank. Figure S1 (page S-2) Modified glass beaker (a) and displacement cone (b) with respective dimensions. Figure S2 (page S-3) Schematic density separation process Figure S3 (page S-6) Formal and calculation example (PP) for the process standard deviation and its projection on the polymer recovery. 1 Figure S1 Modified glass beaker (a) and displacement cone (b) with respective dimensions. 2 Table S1 Grain size distribution of quartz sand <2 µm 0,0 Fine quarz sand 2 - 6,3 µm 1,0 6,3 - 20 µm 1,6 20 - 63 µm 1,2 QS4 QS-A1 63 - 200 µm 87,5 200 - 630 µm 8,7 630 - 2000 µm 0,0 Table S2 Spiked polymer masses in µg. Polymer PE PP PUR PA6 PS PMMA PC PVC PET QS1 48.1 46.7 42.4 49.3 18.9 21.6 4.9 43.9 14.1 QS2 48.1 43.6 40.2 42.1 20.8 20.6 4.9 44.6 14.7 QS3 43.1 44.8 47.5 48.2 19.9 20.6 4.9 43.1 14.4 40.7 42.5 48.5 40.8 21.2 20.0 5.7 40.7 15.8 40.4 47.8 45.3 20 22.2 4.8 46.3 15.5 QS-A2 40.7 43.7 45.8 42.0 20.1 19.3 4.9 42.4 15.3 QS-A3 41.5 40.1 41.5 45.0 20.3 20.3 4.9 40.6 14.9 QS-A4 40.4 40.3 44.7 48.9 21 19.8 5.2 40.4 15.6 Table S3 Spiked number of polymer particles. Polymer PE PP PUR PA6 PS PMMA PC PVC PET QS1 QS2 QS3 QS4 8 8 6 7 6 5 6 18 6 7 7 9 7 6 6 6 18 6 7 9 10 8 6 5 9 18 8 15 8 8 8 10 6 5 20 8 QS-A1 7 8 10 6 5 5 7 15 9 QS-A2 8 7 7 9 9 7 7 20 8 QS-A3 7 8 7 10 9 5 5 20 8 QS-A4 15 8 9 7 8 8 5 20 5 3 Figure S2 Schematic density separation process. 4 Table S4 Polymer specifications. abbreviation polymer PP PE Polypropylene Polyethylene PS Polystyrene PA6 Polyamide-6 Polymethylmethacrylate Polycarbonate MDI-Polyurethane Polyethyleneterephthalate Polyvinylchloride PMMA PC MDI-PUR PET PVC company product name Borealis AG, Wien, Austria Borealis AG, Austria Total Refining & Chemical Polymers, Total Research & Technology Feluy, Belgium Ter Hell GmbH, Germany Evonik Performance Materials GmbH, Germany Teijin Kasei America, US GEBA GmbH HL508FB MG7547S Ter Hell GmbH, Germany K896 Granulat GmbH, Germany Troilit® VB 537-HE Impact 7240 Akulon® K222-D Plexiglas® 7N Panlite® L-1250Y Desmovit® DP LFC 3379 Table S5 Injection Standards. ISTDPY Injection (µg) 9-tetradecyl-1,2,3,4,5,6,7,8-octahydro anthracene cholanic acid anthracene (d10) polystyrene (d8) 0.5 0.5 1.0 1.0 Table S6 Conditions for Pyrolysis-GCMS/Thermochemolysis measurements. Micro furnace pyrolyzer carrier gas curie temperature pyrolysis time transfer line temperature Gas chromatograph injector mode temperature pre-column column flow (const.) temperature program transfer line temperature Mass spectrometer ionization energy scan rate scan range EI-Source temperature quadrupole temperature EGA/PY-3030D (FrontierLabs) Helium 590°C 1 min 320°C 7890B (Agilent) split/split less split 15:1 300°C Trajan P/N 064062; 10 m x 250 μm/ 363 μm VSPD Tubing DB5 (J&W); 30 m x 0.25 mm ID, film thickness 0.25 µm 1.2 ml/min 35°C (2 min) → 310 °C (30 min) at 3°C/min 280°C MSD 5977A (Agilent) 70 eV 2.48 scans/s 50-650 amu 230 °C 150 °C 5 Table S7 Overview of different measurements sequences and accompanied calibrations. QS-A ISTDpy b slope r2 sx0 [µg] n QS PE PP PET PS PVC PC PMMA PA6 PUR d-PS 7.88E-05 8.15E-03 0.93 5.2 10 TOHA 1.25E-02 2.58E-02 0.99 1.46 8 none -4.06E+06 2.77E+06 0.97 0.94 6 none 3.02E+05 1.33E+06 0.98 1 7 none 3.25E+06 7.02E+05 0.9 5 12 TOHA -1.22E+00 2.70E+00 0.95 0.4 6 d-PS 2.50E-01 3.19E-01 0.95 1.7 15 TOHA 2.51E-01 1.70E-01 0.96 3.7 8 TOHA 2.66E-02 6.85E-03 0.98 2.8 5 Anthracene- Anthracene- AnthraceneAnthracene- Anthracenenone d-PS d10 d10 d10 d10 d10 b -4.32E-03 3.22E-02 5.40E-02 1.54E-04 -8.45E+05 3.17E-01 -7.10E-01 2.51E-01 slope 7.41E-03 1.92E-02 1.82E-01 7.39E-02 1.08E+06 2.49E-01 2.58E-01 3.86E-01 r2 0.96 0.98 0.8 0.97 0.99 0.99 0.91 0.92 sx0 [µg] 2.2 2.3 3.1 1.4 1.9 0.2 2.1 3.4 n 5 5 6 5 5 4 6 8 r2 = coefficient of determination. sx0 = process standard deviation. TOHA = 9-tetradecyl-1.2.3.4.5.6.7.8-octahydro anthracene ISTDpy TOHA Table S8 List of polymers and their respective specific indicator ions. Polyethylene Abbreviation PE Polypropylene RI a Indicator ions (m/z) 85 83 82 Alkanes (e.g. C20) -Alkenes (e.g. C20) -Alkenes (e.g. C20) 2000 1994 1987 M (m/z) 282 280 278 PP 2,4-Dimethylhept-1-ene 2,4,6,8-Tetramethyl-1-undecenesb 2,4,6,8-Tetramethyl-1-undecenesc 2,4,6,8-Tetramethyl-1-undecenesd 832 1306 1315 1323 126 210 210 210 126, 70 100, 69 100, 69 100, 69 Polystyrene PS Styrene 2,4-Diphenyl-1-butene 2,4,6-Triphenyl-1-hexene 890 1720 2440 104 208 312 104 91 91 Polyvinyl chloride PVC Benzene Naphthalene 738 1187 78 128 78 128,102,64 Poly(methyl methacrylate) PMMA Methylacrylate Methyl methacrylate 726 775 86 100 55 100, 69 Polyamide PA6 -Caprolactam N-methyl caprolactame 1257 1224 113 127 113 127 Polyethylene terephthalate PET Dimethyl terephthalatee 1504 194 163 Polycarbonate PC p-Methoxy-tert-butylbenzenee 2,2-Bis(4'-methoxy-phenyl) propanee 1240 2065 242 256 164, 149 256, 241 MDIPolyurethane MDI-PUR 4,4‘-Methylenbis(N-methylaniline) e N,N-Dimethyl-4-(4methylamino)benzylaniline 4,4’-Methylenbis(N,N-dimethylaniline) e 2330 2341 226 240 226 240 2354 254 253, 254 Polymer Characteristic decomposition product(s) a RI = Retention index calculated after Van Den Dool 1963, DB-5 column; M = molecular ion, m/z = mass to charge ratio; bIsotactic. cHeterotactic. d Syndiotactic. eOnly after TMAH teatment; bold: indicator ions used for calibration 6 Anthracene -d10 -6.27E-03 7.54E-03 0.99 1.6 4 Table S9 Comparable information on recovery replicates and blank. sample type unit PE PP PET PS PVC PC PMMA PA6 PUR QS1 recovery area 4,423,989 69,749,536 146,911,204 44,489,460 57,876,856 79,473,631 52,603,129 216,781,652 8,299,622 QS2 recovery area 27,443,610 86,370,510 76,219,166 99,725,655 5,295,626 QS3 QS4 recovery area 2,365,030 57,724,282 77,197,126 45,917,973 134,302,177 76,988,927 25,326,922 98,979,717 5,444,208 recovery area 1,814,458 59,692,763 91,303,143 71,910,368 40,685,610 67,179,622 47,915,105 110,531,649 7,760,737 QS-A1 recovery area 157,769 16,848,259 7,017,346 43,320,480 21,063,230 16,630,824 11,932,827 820,954 QS-A2 recovery area 98,896 12,016,237 75,259,770 11,205,206 42,564,412 37,494,823 29,214,028 14,11,615 1,022,456 QS-A3 QS-A4 recovery area 192,270 10,152,031 52,272,313 14,382,739 24,386,681 31,431,327 17,894,426 15,795,688 862,991 recovery area 179,347 11,104,362 49,782,414 14,594,378 35,814,383 44,873,513 17,881,931 21,637,572 1,175,387 QS-AB1 QS-AB1 quantified 895,447 43,990,738 179,307,147 41,640,345 blank area n.d. n.d. 1,188,910 184,206 3,090,954 25,619 1,267,267 476,340 n.d. blank µg n.d. n.d. 0.58 -0.09 -0.23 0.46 4.42 -0.10 n.d. Figure S3 Formal and calculation example (PP) for the process standard deviation and its projection on the polymer recovery. 7