Title Page
Contents
Abstract 11
요약문 13
1. Introduction 15
2. Theoretical background 19
2.1. Plastics identification and analytical methods 19
3. Experimental methods 23
3.1. Sample collections from artificial tears 23
3.2. Surface characterization of PE released from artificial tears 27
3.3. Materials 27
4. Results and discussion 28
4.1. Sample preparation and surface characterization 28
4.1.1. Substrate selection using Polystyrene Latex (PSL) 28
4.1.2. Plastic detection by Raman spectroscopy 32
4.1.3. Characterization of plastic by combination of Raman and SEM 38
4.2. Quantification of plastics from eye drop 41
4.2.1. Quantification of plastics by Py-GC/MS and Raman analysis 41
4.2.2. Detected MNP size distribution 48
5. Conclusion 54
6. References 56
Table 1. Preparation of samples. 26
Table 2. Quantitative analysis by Py-GC/MS of S1, S2, and S3 45
Table 3. The number of relative particles populated on filters for individual samples. 47
Figure 1. Raman spectra of relevant polymers, "Fingerprint" region and region for C-H stretching modes of alkyls, alkenes, and aromatic protons are highlighted. 21
Figure 2. Mass to diameter correlation of spherical MP particles with a density of 1 g/cm³. 22
Figure 3. Sample collection for affirmation (a) the released MNP by opening artificial tears (b) the difference in plastic leakage by the order of dropping... 25
Figure 4. Conventional Raman spectrum of bulk PS and Raman spectra of 500 nm PSL particles on Si wafer and Au standard TEM grid. 29
Figure 5. Raman spectra of random 1 μm PSL on Au membrane filter. 30
Figure 6. SEM image of 1 μm PSL detected on Au membrane filter. 31
Figure 7. Raman spectra of artificial tears bottle (LDPE) and standard PE powder. 34
Figure 8. Raman spectra of (a) artificial tears bottle consisted of LDPE (black), MP released from eye drops (red), and Dried eye drop solution... 35
Figure 9. (a) The optical image of MP released from eye drops corresponding with Raman spectrum of Fig.1, (b) the corresponding high... 36
Figure 10. SEM images of standard PE powder with various size and shape. 37
Figure 11. Raman spectra, optical, and SEM images of diverse MNP released from eye drops sized with (a) 580 nm, (b) 1.1 µm, (c) 2.3 µm, (d)... 40
Figure 12. Total Ion Chromatogram (TIC) and Extract Ion Chromatogram (EIC) of S1 by Py-GC/MS. 44
Figure 13. Five investigated areas. 46
Figure 14. Size fraction of MNP detected on S1, S2, S3, and S4. 50
Figure 15. Size fraction of MNP detected on S1-S4 and size distribution of MNP detected on artificial tears inner wall. 51
Figure 16. SEM images discovered on the wall of artificial tears bottle before washing; (a)-(b) eye drops, (c)-(f) PE particles. 52
Figure 17. SEM images of PE particles discovered on the wall of artificial tears bottle after washing. 53