Partner in Mission Oloid Engineering GmbH
26. June 2025
Microplastics and Bio-based Products
3. July 2025
Microplastic Analytics: Between Precision and Pragmatism New approaches and the limitations of established methods
Microplastic analytics is at a turning point. While the scientific community is still struggling to standardize procedures, time is running out: particles already permeate all environmental compartments, and we urgently need reliable, scalable analysis methods. Fluorescence microscopy is proving to be a promising alternative to established but limited methods such as FT-IR spectroscopy.
The Limitations of FT-IR Spectroscopy: Accuracy with Challenges
Fourier transform infrared spectroscopy (FT-IR) is considered the gold standard for microplastic identification, but it has significant practical limitations. The method fails for particles smaller than 10–20 μm, which excludes a significant proportion of the environmentally relevant microplastic fraction. Furthermore, FT-IR analysis requires time-consuming sample preparation, expensive infrastructure, and highly qualified operators.
Interference from organic components, which necessitates complex sample purification, is particularly problematic. This makes the method practically unsuitable for routine analyses or large-scale monitoring programs. The high cost per analysis further limits the number of samples that can be examined and delays scientific findings on the actual microplastic contamination.
Fluorescence microscopy: Speed meets Precision
Fluorescence microscopy allows for very fast and relatively inexpensive analysis, making it well-suited for screening procedures. The method is based on the specific staining of plastic particles with fluorescent markers, making even the smallest particles in the micrometer range detectable. Microplastics can be identified relatively easily and quickly using a fluorescence microscope if they have been stained with a fluorescent dye.
The significant advantages of fluorescence microscopy lie in its accessibility and scalability: Lower acquisition costs, shorter analysis times, and the possibility of automation using image analysis software make the method accessible to a wider range of users. This opens completely new perspectives for citizen science projects and decentralized monitoring approaches.
Citizen Science: Harnessing the Power of Community
Involving the public in microplastic sampling addresses untapped potential for large-scale environmental monitoring. Using standardized analytical kits, citizens can systematically collect data from a wide variety of environmental compartments – from beaches to rivers to urban stormwater.
This participatory research would not only exponentially expand the database but also raise public awareness of the microplastic issue. However, precise method standardization and quality control are prerequisites to ensure scientifically usable results.
Not all fluorescent markers are created equal
The selection of suitable fluorescent markers is crucial for the quality of microplastic detection. Established microplastic markers such as Rhodamine B and Nile Red have significant weaknesses that call into question their suitability for standardized microplastic analysis.
The Rhodamine B Problem
Rhodamine B exhibits low selectivity for plastics and simultaneously stains organic materials such as algae, bacteria, and detritus. This leads to high false-positive rates, requiring laborious manual follow-up testing. Rhodamine B is used as a nonspecific fluorescent marker, which already highlights the fundamental problem.
The Nile Red Limitation
Although Nile Red binds preferentially to lipophilic structures, it does not sufficiently discriminate between different types of plastics and organic lipids. Nile Red fluoresces in the red range up to the near-infrared, which can lead to spectral overlap with natural fluorescence.
Both markers are also pH- and solvent-dependent, which complicates their application in complex environmental matrices and leads to inconsistent results.
Innovation through abcr eco Wasser 3.0 detect MP-1
The abcr eco Wasser 3.0 detect MP-1 system systematically addresses the weaknesses of conventional fluorescent markers. Wasser 3.0 detect develops new markers that enable microplastics to be stained with less error and without complicated sample preparation.
New fluorescent marker delivers superior selectivity and methodological efficiency
The MP-1 marker was specifically developed for the detection of plastic polymers and exhibits minimal cross-reactivity with organic materials. This drastically reduces false positives and enables direct quantification without complex follow-up testing.
The marker was developed through years of research to selectively stain microplastics. Compared to other methods, the advantage of fluorescence microscopy lies in its speed and measurement efficiency. Simplified sample preparation enables high-throughput analysis, which is essential for comprehensive environmental monitoring.
Due to reduced analysis times and the reduced need for highly qualified personnel, the cost per analysis is significantly reduced. This makes regular monitoring programs affordable, even for smaller institutions.
Why Rhodamine B and Nile Red Hinder Standardization
Standardization of microplastic analysis requires reproducible, robust, and selective methods. Rhodamine B and Nile Red do not meet these criteria.
- Lack of reproducibility: Both markers exhibit strong dependence on environmental parameters such as pH, ionic strength, and temperature. This leads to laboratory- and user-specific variations that prevent international standardization.
- High false-positive rate: Nonspecific binding to organic materials requires complex validation steps, which reduce analytical throughput and create additional sources of error.
- Spectral interference: The broad emission spectra of both markers overlap with natural autofluorescence, making unambiguous discrimination in complex environmental samples difficult.
Outlook: Towards a Standardized Future
Microplastic analysis is facing a paradigm shift. Innovative fluorescent markers like MP-1 are paving the way for standardized, cost-effective, and high-throughput analytical methods. The integration of citizen science approaches could exponentially expand the data pool while simultaneously raising public awareness.
However, this progress requires a critical evaluation of established methods and the resolution to replace proven but limited approaches with innovative solutions. The era of laboratory-specific, ad hoc methods must give way to systematic, internationally harmonized microplastic analysis.
Only through this methodological revolution can we determine the true extent of microplastic contamination and develop evidence-based solution strategies. The technology already exists – now it is a matter of consistent implementation.
