The omnipresent occurrence of microplastics and the expected consequences are subject of modern research and the topic receives more and more public awareness. Due to the fact that plastic waste is degrading only very slowly the amount of microplastics in the environment is steadily increasing.
In particular, the contamination of the world‘s oceans is a problem. Currently, an annual entry of microplastics into the world‘s oceans of about 210 g per person or a total of approximately 1.5 megatons is estimated. The uptake by marine organisms and fish results in a contamination of the human food-chain through microplastics including substances such as plasticizers or adsorbed pollutants.
According to definition, polymer particles with a diameter of less than 5 mm are referred to as microplastics particles (MPP). Depending on their origin, they are further subdivided into primary and secondary particles. Primary particles are those which are specifically produced industrially like for instance peeling particles in cosmetic products. Secondary microparticles are formed by physical, biological and chemical degradation of macroscopic plastic parts and are the main source of all released microparticles. They are mainly formed by the degradation of improperly disposed plastic waste, tire abrasion and washing of synthetic textiles.
Instrumentation and Software
HYPERION FTIR Microscope
SENTERRA II Raman Microscope
OPUS Spectroscopy Software
A high sample throughput combined with reliable identification of even the smallest particles is possible with Microspectroscopic FTIR . This methods are universally applicable and permit the selective analysis of individual particles with a size of a few micrometers. The rapid analysis of larger accumulations of microplastics particles is also possible by means of automated grid measurements.
FTIR analysis of microplastics
Fourier transform infrared (FTIR) spectroscopy is a proven method for the identification of all types of polymers. It allows a reliable differentiation between substances of natural and synthetic origin and allows determining the polymer type (see figure 1). Typically, the identification is carried out by means of an automated comparison against extensive spectral libraries.
With conventional FTIR spectrometers, it is already possible to easily examine larger microparticles. In comparison, FTIR microscopy allows the analysis of single particles with a size of only a few micrometers. Depending on the size of the particle, it is even possible to record several spectra at different points on a single particle.