Microplastic Solution Library 1.1

Important: How to best use the library
This Raman spectral library is designed for the identification of common and uncommon synthetic polymer microparticles and is suitable for all environmental sample types. Below are the reasons behind its structure:

Composition of the library
The library contains 30 spectra in total: 28 synthetic polymers and two minerals (carbonate and silicate). Only a single spectrum is included for each polymer type so as not to overload the library or increase spectral matching times unnecessarily.

Exclusion of pigmented plastics
The library does not contain coloured (pigment-containing) plastics because specific pigments exhibit unique Raman signals. Since the same pigments can be used across different polymer types, a pigment is not relevant to polymer identification and may lead to misclassification.

Guidance for Similarity-Based Searches (SBS)
When using the library in Similarity-Based Searches (SBS), spectral matches must be confirmed by a trained interpreter even if the hit-quality index (HQI) is high. HQIs are only referential and should be used as a primary sorting tool, not as a decisive measure of identification. We recommend setting a lower threshold below which polymers are excluded (e.g., 80%; depending on the polymer type) and above which spectral matches are manually evaluated by a trained interpreter.

Spectra were collected from in-house plastic and non-plastic compounds. compounds were measured using a 532 nm He–Cd laser (7.2 mW, 8% power) with a 100× objective, yielding a lateral resolution of ~1 µmSpectra were collected from 200–3400 cm⁻¹ with a 600 g/mm grating and ~1 cm spectral resolution.der of 1 cm^-1.

Acquisition parameters:
Raman measurements were carried out at 20°C using a Horiba LabRAM Soleil (Jobin Yvon, France). The samples were excited at 8% (7.2 mW) power output with a high stability air-cooled He–Cd 532 nm laser diode utilizing a Nikon LV-NUd5 100x objective. The lateral resolution of the unpolarized confocal laser beam was on the order of 1 µm. Spectra were generated in the range of 200–3400 cm−1 using a 600 grooves/cm grating with a 100 µm split. The spectral resolution was on the order of 1 cm−1. Using the Spectragryph spectral analysis software V1.2.17d (Dr. Friedrich Menges SoftwareEntwicklung, www.effemm2.de/spectragryph), all raw spectra were processed using adaptive baseline correction with 15% coarseness.

About the data:
First row: Spectral range in cm^-1.
Second row: Relative intensity from 0 to 1.
Data can be visualized in Excel, SpectrGryph or other spectroscopy software.

Abbreviations:
ABS: Acrylonitrile butadiene styrene
CA: Cellulose acetate
PA12: Polyamide 12
PA6,6: Polyamide 6,6
PA6: Polyamide 6
PAN: Polyacrylonitrile
PBAT: Polybutylene adipate terephthalate
PBT: Polybutylene terephthalate
PC: Polycarbonate
PE: Polyethylene
PET: Polyethylene terephthalate
PBT: Polyhydroxybutyrate
PI: Polyisoprene rubber
PLA: Polylactic acid
PMMA: Poly(methyl methacrylate)
POM: Polyoxymethylene
PP: Polypropylene
PS: Polystyrene
PSU: Polysulfone
PTFE: Polytetrafluoroethylene
PU: Polyurethane [thermoset]
PVA: Polyvinyl alcohol
PVC: Polyvinyl chloride
PVDF: Polyvinylidene fluoride
SBR: Styrene butadiene rubber
SPA: Sodium polyacrylate
TPU: Polyurethane [thermoplastic]

Changes from version 1.0 to 1.1
1) Spectrum of diopside removed.
2) Spectrum of silicate added.