A beaker method for determination of microplastic concentration by micro-Raman spectroscopy.Fourier-transform infrared (FT-IR) spectroscopy method for measuring small microplastic (SMP) concentration in marine environment is time-consuming and labor-intensive due to sample pre-treatment.  In contrast, Raman spectroscopy is less influenced by water and can directly measure SMP samples in water, making it a more efficient method to measure SMP concentration. 
Raman spectroscopy
A beaker method for determination of microplastic concentration by micro-Raman spectroscopy.Fourier-transform infrared (FT-IR) spectroscopy method for measuring small microplastic (SMP) concentration in marine environment is time-consuming and labor-intensive due to sample pre-treatment. 
Fourier-transform infrared (FT-IR) spectroscopy
Further investigation found that there is a significant functional relationship between correlation coefficient of sample spectra and the concentration of PE particles, and such relationship can be modelled by Langmuir model. 
Langmuir model