A novel method for extraction, quantification, and identification of microplastics in CreamType of cosmetic products

Soohyun Lee,Tai Gyu Lee

doi:10.1038/s41598-021-97557-0

Abstract

The objective of this study was to develop an accessible and accurate analysis method for microplastics that have been unintentionally added to cream cosmetic products. An experiment was performed on three cleansing creams in rich and viscous formulations. A spiked sample was prepared by adding polyethylene (PE) microspheres to the cleansing creams. After removing cosmetic ingredients from the creams using chemical digestion, damage to the PE microspheres was identified using Fourier transform infrared (FT-IR) spectroscopy. Field emission scanning electron microscopy (FE-SEM) images were obtained before and after digestion and used to characterize the morphology of the PE microspheres. The highest digestion efficiency was obtained using a chemical digestion method consisting of heating and stirring a sample in a 10 wt% KOH solution at 55 °C and 300 rpm for 5 days and did not damage the PE microspheres. The Nile red (9-diethylamino-5H-benzo[α]phenoxazine-5-one) staining method was effective in identifying small microplastics (< 106 μm). The optimal staining conditions are 5 μg/ml Nile red in n-hexane for green wavelengths.

Highlights

The objective of this study was to develop an accessible and accurate analysis method for microplastics that have been unintentionally added to cream cosmetic products
The Ministry of Food and Drug Safety (MFDS) test method has limitations: (1) the cosmetic ingredients in all formulations are not completely removed by pretreatment with only purified water and ethanol; (2) semi-solid substances, such as sucrose or wax in cosmetics, can be misidentified as solids; (3) as was recently reported for bottled w ater[22,23,24,25], the method is limited to analyzing microplastics that may have been unintentionally added to cosmetics; and (4) the expensive Fourier transform infrared (FT-IR) microscope and metal filters required for analysis require specialized fabrication, preventing universal applications
PE microspheres were added to viscous cleansing creams, and the resulting mixtures were chemically digested with diggerent solutions to pretreat organic matter to determine the optimal solution

Summary

Introduction

The objective of this study was to develop an accessible and accurate analysis method for microplastics that have been unintentionally added to cream cosmetic products. The MFDS test method has limitations: (1) the cosmetic ingredients in all formulations are not completely removed by pretreatment with only purified water and ethanol; (2) semi-solid substances, such as sucrose or wax in cosmetics, can be misidentified as solids; (3) as was recently reported for bottled w ater[22,23,24,25], the method is limited to analyzing microplastics that may have been unintentionally added to cosmetics; and (4) the expensive FT-IR microscope and metal filters required for analysis require specialized fabrication, preventing universal applications. The objective of this study is to find an optimal digestion solution for the pretreatment of cosmetics in cream formulations and develop an analysis method for cosmetics that can detect all intentionally and unintentionally

Objectives

Methods

Conclusion