Analysis example
"Please take a moment to explore our microplastic analysis example. It provides valuable insights into our typical workflow and the challenges we navigate to ensure the production of reliable microplastic data. Your interest is appreciated."
CEO and founder of MPS
Oskar Hagelskjær
1
Sample pre-treatment
On the same day that we receive your sample, the appropriate laboratorial manipulation is initiated, to isolate the microplastics within. The goal is to transfer as many microplastic onto the filter membrane meant for analysis, whilst at the same time, avoiding procedural contamination.
This first step often requires
digestion to remove non-plastic
organic material within the matrix,
as well as density separation which
further isolates the microplastics within,
by removing heavy particles such as minerals
2
Automated vibrational microspectroscopy
Depending on your needs we can detect even the smallest microplastics down to 1 µm in diameter. If particles below or above a certain threshold are irrelevant to you, we simply adjust our parameters to meet your requirements.
To achieve statistical significance, we analyze the chemical signature of 10,000 - 20,000 individual particles using state-of-the-art Raman microspectroscopy. We have automated the acquisition procedure to increase the number of analyzed particle otherwise impossible, and further, to remove the potential for operator bias.
3
Computer vision-supported data treatment
By combining state-of-the-art computervision with artificial intelligence, we have designed a system capable of discerning between individual particles based on their visual appearance, in the same way a human would do.
We are not fully dependent automation. The obtained spectra are matched with our extensive spectral library. Matches below a given hit quality index (HQI) threshold are automatically sorted out, after which potential candidates are inspected by a trained interpreter, to avoid false positives.
4
Negative control (blank correction)
To correct for false positives, we analyze a plastic-free to determine the plastic input of the protocol. The found plastic will be subtracted from the trout sample.
5
Positive control (recovery correction)
To perform a recovery experiment with microplastics that best ressemble the type and size within the sample, we used red polyethylene PrecisionMP™ fragments in the 5-100 µm range to determine the analytical microplastic recovery of the protocol. Knowing the exact number of microplastic fragments within the spike sample is a big advantage because we reduce uncertainty significantly. Furthermore, because we spike we fragments in of varying size, we were able to determine the microplastic recovery within specific size ranges.
Average recovery was determined at 70 ± 6% and was stable at a satisfactory level across all present size ranges
6
Comprehensive data normalization
After correcting for procedural microplastic loss and contamination, we normalize data onto 1 gram of trout muscle tissue. We determine a microplastic content of 1800 microplastics which amounts to 0.13 µg/g. This corresponds to a concentration of 0.000013 mass% or 0.13 PPM (parts per million).
Note: As this sample was meant only to serve as an example, statistical validity was not important. For your sample we recommend replicating the experiment at least three times, in order to achieve statistical significance of the results.