• microplastic analysis
• oxidation treatment
• Raman microspectroscopy
• sample pretreatment

Microplastic pollution has been reported even in the world’s most remote regions and their analysis is one of the current challenges of the scientific community. In this work, Raman microspectroscopy was used to identify and quantify microplastic particles down to 1μm in ocean water samples. Particle quantification was possible thanks to the TUM-ParticleTyper 2 software. In particular, research focused on the development of a sample preparation procedure for efficient Raman analysis. (In)organic matrix can hamper the correct identification of microplastic particles, therefore matrix removal is a crucial point in microspectrometric analysis. Different standard procedures (alkaline digestion, Fenton reaction, treatment with ethylenediaminetetraacetic acid and sodium dodecyl sulfate) were compared to the generation of hydroxyl radicals in hydrogen peroxide through UV light irradiation. The combination of hydrogen peroxide and UV light was tested for the first time as sample pretreatment for microplastic analysis. The effects of reaction parameters such as irradiation time and hydrogen peroxide concentration were investigated. The oxidation effect of the treatment was demonstrated measuring the bleaching of an algae extract suspension with a UV-VIS spectrophotometer. Further steps include optimization and validation of the method and application of the treatment on ocean water samples.