Data for: Raman microspectroscopy and laser-induced breakdown spectroscopy for the analysis of polyethylene microplastics in human soft tissues

Data from Raman microspectrometry, LIBS, XRF, and particle sizer analysis supports the findings in the published article named Raman microspectroscopy and laser-induced breakdown spectroscopy to analyze polyethylene microplastics in human soft tissues. The aim of this research is to present the optimized protocol for the detection and analysis of microplastics in biological samples.

The tonsil tissue is used for this experiment, and the workflow consists of a few steps: 1. digestion, 2. filtration, 3. analysis. 

The presented dataset includes the data for verifying the validity of this proposed protocol and the data from clinical experiments done on tonsils where the protocol is applied. We are focusing only on PE microplastics as they are one of the most frequent plastic types in the environment. 

Firstly, the data from the particle sizer show the size distribution before and after KOH treatment, which is necessary for digestion. We are testing if the particles are not affected by the KOH solution. The data are listed in an Excel sheet where the individual detected PE particle size [µm] and their frequencies [%] are annotated. The data are separated into 2 tables in one sheet - 1st represents data collected before KOH and the 2nd after KOH treatment. 

To test the limits of our selected systems for microplastic detection, we included the data from Raman and LIBS under the file ‘limitations.’ The different sizes of PE particles, from tens to 1 µm, were analyzed, and the spectra can be retrieved in the folders. The signal intensity can be observed to see the detection limits. For the Raman analysis, the particles were located on the filter. For LIBS, the particles were embedded in epoxy to enable the detection of PE particles in tens of microns. The Raman data are in .txt files and can be opened in any adequate software (Matlab, R, Python, etc.). LIBS data are in specific .libsdata format, which can be opened by LibsAnalyzer software by Lightigo. 

The clinical experiment was done on tonsil tissue. The tissue was disgusted and filtered. Then, the filters were analyzed. The dataset presents two sample groups: 1. control-native tissue and 2. test-spiked tissue with PE particles. The data from Raman analysis include both, with the aim to confirm the presence of PE particles in the test sample and to exclude the contamination in the control sample. The spectra are again in .txt files. In the case of control, spectra from unclassified particles are presented. For these reasons, the LIBS and XRF were run to exclude the possibility of the presence of polymeric material on the filter of the control sample. The analyzed chemical elements by LIBS for both samples are in the ASC file. Furthermore, individual PE particles were also analyzed on LIBS to obtain reference results for test samples with added PE microplastics. In the case of XRF, data from the empty filter, control, and test samples are included, each in a .txt file. Individual detected chemical elements and their intensities can be retrieved in the tables.