A Multispectral Pulsed-Transmission Laser-Diode Sensor Concept for Real-Time In Situ Assessment of Microplastics in...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Optical Engineering

Background:

• Current microplastic monitoring methods require extensive sample preparation and laboratory analysis, hindering real-time assessment.
• There is a critical need for in situ techniques that can analyze microplastics directly in aquatic environments.

Purpose of the Study:

• To propose and establish the measurement model for a novel optical sensor concept for real-time, in situ microplastic assessment.
• To demonstrate the feasibility of using multispectral pulsed transmission for microplastic identification and quantification.

Main Methods:

• Development of an optical sensor concept based on multispectral pulsed transmission in the visible range.
• Utilizing synchronized laser-diode lines and analyzing the directly transmitted signal through an active sensor volume.
• Employing the Urbach-tail formalism for polymer absorption and Fresnel-based calculations for light redirection to model particle interactions.

Main Results:

• A model-based proof of concept for an optical sensor capable of real-time microplastic assessment was established.
• The proposed method allows for decoupling of particle size and shape through an effective optical length.
• The sensor concept has the potential to differentiate between structural modifications of identical polymer compositions based on multi-wavelength absorption signatures.

Conclusions:

• The developed measurement model and inversion scheme provide a foundation for experimental verification of the proposed optical sensor.
• This approach offers a promising pathway towards rapid, in situ microplastic monitoring in aquatic systems.
• Further validation with real reference particles is necessary to confirm environmental applicability.