近海微塑料含量的相干反斯托克斯拉曼光谱成像研究

由于塑料工业的发展,微塑料成为一种主要的环境污染物.它在自然界中不易降解,对人类的生存环境及健康都存在不可忽视的潜在危险.因此,环境中微塑料的检测和分析,成为了近年来研究的热点问题.目前人们大多数采用浮选法、密度分离法、离心法等方法提取微塑料,然后放在显微镜下进行目视观察,并结合拉曼光谱分析、傅里叶红外光谱分析、高光谱...

Research on Coherent Anti-Stokes Raman Spectroscopy Detection of Microplastics in Seawater and Sand

With the development of the plastic industry, microplastic, which is difficult to degrade in nature, became one of the main environmental pollutants. Moreover, it harms human health as it accumulates within the organisms and environment. Therefore, the detection and assessment of microplastics in the environment have been highly concern in recent years. Most the works first extract microplastics from samples by flotation, density or centrifugation separation system, and then find the microplastics under a microscope directly or combine with Raman spectroscopy, Fourier Transform infrared spectroscopy, Hyperspectral imaging and other methods for analysis and identification. Nonetheless, these methods require a long waiting time for pretreatment and could easily be affected by subjective factors. To identify whether the microplastics are in environmental samples or not quickly and accurately, we propose to use the multi-channel image acquisition, including white light channel imaging and Coherent Anti-stokes Raman Scattering (CARS) spectral imaging. CARS spectral imaging is a non-invasive and non-destructive real-time imaging method based on chemical bond vibration. Microplastic with a diameter of 10 μm polluted seawater and sand were simulated by the collected seawater/sand mixing with polystyrene microspheres. We detected the distribution of polystyrene in seawater intuitively through multi-channels image acquisition. The multi-channel image of polystyrene microspheres in the sand was collected and compared with the image by Raman spectroscopy. In the detection of Raman spectroscopy, the signal of polystyrene microspheres is easily interfered with by the fluorescence signal of sand, and only when the laser is focused on the location of polystyrene, does the weak signal can be detected. In the multi-channel image acquisition and detection, polystyrene microspheres can be seen in the sand, and we used a simple morphological analysis and filtering algorithm to make the microplastic signal obvious. Multi-channels image acquisition for microplastics detecting (in seawater and sand) without pretreatment is fast and simple, which has a certain potential for detecting microplastics in the environment value.