Comparative study of matrix etching methods for the separation of microplastics from environmental samples

Microplastics are plastic particles that do not exceed 5 mm in size. They are found in every ecosystem and are even present in living organisms. An important aspect of studying this contamination is the separation of microplastics from samples. Testing such samples is necessary but time-consuming. Some methods can damage microplastics or be ineffective. This study aimed to test the most commonly used matrix etching methods, using different parameter configurations such as time, temperature, and shaking. The study was also conducted on two types of environmental samples: bulk and more compact, to provide more detailed information. By using the same matrices, the estimated yield was adequate. Oxidative and acid etching methods were used. The most advantageous method in terms of performance for both sample types was oxidative digestion with a high concentration of oxidant. However, digestion with half the concentration also proved to be satisfactory regarding efficiency and safety, as the more important parameters in the oxidation process were temperature and contact time.