Research On The Detection Method Of Microplastics In Fish

The plastic burden on the environment is a rising threat,and rising evidence shows that aquatic organisms ingest microplastics.In order to obtain relevant scientific knowledge,the effective extraction of plastic in biological is an important experimental method.Most of the existing extraction methods use different digestion reagents to digest biological tissues,and perform qualitative and quantitative analysis on retained microplastics.As the research of microplastics is still in its infancy,there is no unified analytical standard for the analysis of microplastics in living organisms and the means of digestion reagents used are not the same.Some digestive methods are not effective,and the tissue residue is too much,which leads to the interference of the subsequent micro plastic detection.Some digestion methods have an important effect on plastic form or chemical structure,which results in false detection results.This requires an efficient and rapid method for the digestion of organism,but it will not corrode plastic polymers.This article takes the fish digestive tract as the research object and discusses the digestion and extraction effects of different digestive protocols.This article mainly selected the digestion and extraction effect of two digestive reagents,acids and oxidants.In this paper,the digestion of fish digestive tract were tested with different concentrations of H₂O₂,HNO₃,HClO₄ and different concentrations of HNO₃ and HClO₄ combined reagents,and different concentrations of HNO₃ and H₂O₂ combination reagents at room temperature?25°C?.Observe and evaluate the effects of polyethylene?PE?,high density polyethylene?HDPE?,polyamide?PA?,polystyrene?PS?,polyethylene terephthalate?PET?,acrylonitrile-butadiene-styrene?ABS?and acrylonitrile-styrene?AS?copolymers 7 common plastics in environments.It is found a ratio of 1:4 HNO₃?7.2mol/L?/H₂O₂?9.97mol/L?combined solutions at room temperature for 12 hours,can digest the digestive tract,and does not cause significant corrosion to plastic particles.Due to the difference in digestive tract samples of fish,some of the samples have grease blocks after digestion,affecting the filtration efficiency.The surfactant sodium dodecyl sulfate(C₁₂H₂₅SO₃Na)solution was added to this and ultrasonication was performed for 30 minutes to effectively remove residual grease.To compare the changes,the plastic particles were weighed,and Raman spectroscopy was used to spectral scanning before and after digestion.Except for the weight change of polyamide?PA?was+8.74±0.008%,the weight changes of the other seven plastics were all between-0.022±0.001%and+0.113±0.002%without significant changes.Before and after the digestion,the peak position of the polyamide?PA?has a certain offset and changes greatly.The spectra of the other six kinds of plastics have small changes and can still be clearly identified by the spectra after digestion.It means that the digestion process will not cause serious corrosion of these plastic particles,and will not reduce the detection rate of plastic in fish.Finally,analyze the recovery rate.Using 4 sizes of 0.01-0.1mm,0.1-0.5mm,0.5-1mm,and 1-5mm of 7 plastics.The recovery experiment was performed and found that for the same type of plastic particles,the larger the particle size,the greater the recovery rate.The average recovery rate of each particle size range reached more than 90%.When the particle size range reached 1-5mm,the average recovery rate of each plastic reached more than 95%,and even reached 100%.This method can effectively recover the microplastics in fishes.As a consequence,the present method saves time,minimizes the loss of material and the risk of contamination,and facilitates the identification of plastic particles and fibers,thus providing an efficient method to detect and quantify microplastics in the digestive tract of fishes.