5:15 PM - 7:15 PM
[AAS11-P03] Raman spectroscopic analysis of atmospheric plastic particles using near-infrared laser
Keywords:microplastic, nanoplastic, microscopic Raman
The production of plastics has increased since 1950. Plastic particles have the potential to impact the environment and human health. Plastic particles have been found in the atmosphere. However, it is unclear how many plastic particles are present and what particle size is dominant in the atmosphere. This is partly due to the lack of methods to characterize plastic particles, particularly for particles smaller than 5 µm. In this study, we aim to analyze plastic particles using microscopic Raman spectroscopy and to confirm whether plastic particles are found in ambient samples. We focus on plastic particles smaller than 5 µm.
A Raman spectrometer was home-made using a 785-nm laser as an excitation wavelength. Using this laser suppresses the fluorescence emission of samples upon Raman measurements. First, polystyrene latex (PSL) particles were used to confirm the minimum particle size that the home-made Raman system can analyze. The particle sizes of PSL particles used in the experiments were 20, 10, 6, 3, 1, and 0.5 µm, respectively. Next, we analyzed laboratory-generated particles from the combustion of plastic samples mixed with rice straw (RS). The plastic samples used include polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET). The rice straw was dried under the sun and stored in a sealed bag with a silica gel desiccant. The combustion experiments were performed in a combustion furnace. The generated particles were collected on a quartz filter. Ambient samples collected in Hanoi were also analyzed. They were collected on a Si wafer using a nanosampler and a multi-nozzle cascade impactor. The sampling time was 4 hours in both samples, and the samples were stored in a desiccator before use. In our presentation, we will discuss the performance of the Raman system based on acquired Raman spectra.
A Raman spectrometer was home-made using a 785-nm laser as an excitation wavelength. Using this laser suppresses the fluorescence emission of samples upon Raman measurements. First, polystyrene latex (PSL) particles were used to confirm the minimum particle size that the home-made Raman system can analyze. The particle sizes of PSL particles used in the experiments were 20, 10, 6, 3, 1, and 0.5 µm, respectively. Next, we analyzed laboratory-generated particles from the combustion of plastic samples mixed with rice straw (RS). The plastic samples used include polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET). The rice straw was dried under the sun and stored in a sealed bag with a silica gel desiccant. The combustion experiments were performed in a combustion furnace. The generated particles were collected on a quartz filter. Ambient samples collected in Hanoi were also analyzed. They were collected on a Si wafer using a nanosampler and a multi-nozzle cascade impactor. The sampling time was 4 hours in both samples, and the samples were stored in a desiccator before use. In our presentation, we will discuss the performance of the Raman system based on acquired Raman spectra.