Detection of Microplastics in CSIC Laboratories

1. Mass Spectrometry

Chromatography is an essential technique for detecting microplastics. It makes use of an ionization source and a transfer system to separate and detect compounds.

1.1 Liquid chromatography with mass spectrometry

This technique is used to analyze water-soluble compounds. It has a vast analytical capacity, allowing the determination of molecular weight with precision up to 4 decimals. This allows for very accurate and meticulous detection.

1.2 Interpret masses and selectivity

Chromatography can detect all masses, although it may have low selectivity. Through this technique, it can be observed that the most volatile contaminants come out first, followed by the less volatile ones and with larger structures. Each peak in a chromatogram represents a different chemical compound.

2. Pyrolysis

Pyrolysis does not use an injector directly, but a pyrolysis system with buckets. In this process, a filter is placed facing downward, and a specific temperature is applied. Argon gas is used to pyrolyze and volatilize parts of the microplastics present in the sample.

2.1 Reference patterns

Reference patterns are used to characterize microplastics by retention time and mass spectrum. These patterns are essential for identifying and comparing the polymers present in the samples with the known ones.

For example, in this case we have polystyrene and we observe how we find it superimposed with another compound. In these cases, a more thorough analysis is needed to know which compound it is.

3. Additional detection techniques

3.1 Raman and IR spectroscopy

Raman spectroscopy is one of the most expensive techniques for detecting microplastics, while IR spectroscopy is considered unfeasible for some applications due to its limitation in detecting particles smaller than 50 microns.

3.2 Sample preconcentration

This technique is essential for analyzing drinking water from different parts of the world. A sample is pre-concentrated on a filter, and then various techniques are used to identify the microplastics.

3.3 Other techniques

Mass spectrometers and techniques like spectroscopy are used to detect and analyze microplastics in the air. Moreover, work is being done on impedance-based techniques to detect microplastics with the help of Ramon Bragós and Sandra Bermejo.

4. Implications for human health

Microplastics can have various implications for human health. Studies have been conducted to determine whether people inhale microplastics through masks, with results indicating that they do not. However, it has been found that microplastics can pass through the blood to the placenta.

5. Regulations and guidelines

The increasing presence of microplastics has led to the adoption of new regulations and guidelines. From 2024, it will be mandatory to analyze microplastics in river and drinking water. In addition, a new directive is expected for 2025-2027 that will require washing machines to be equipped with a device to remove microplastics.

6. Final considerations

Microplastics are a growing concern worldwide. Advanced detection techniques such as chromatography and pyrolysis are essential for understanding the extent of this issue. Future regulations and guidelines will play a key role in the fight against microplastic pollution.