Microplastic Particle Measurement With Angled Spectral Detection

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Solution Overview

Problem

Existing laboratory methods for measuring microplastic particles in liquids are complex, time-consuming, and limited to small sample volumes, making them inefficient for large-scale analysis.

Innovation Solution

An arrangement and method utilizing a measuring channel with a specific angle between the optical axis of the measuring beam path and the detection direction (45° to 135°) to enhance signal quality, combined with a spectrometer and detection optics to identify particle material based on inelastic scattered light spectra, and a high-sensitivity detector system to improve measurement speed and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional laboratory methods are used for measuring microplastic particles, then measurement accuracy is maintained, but measurement speed and throughput are limited

Engineering Contradiction:
Improvemeasurement throughputVSAvoidmeasurement time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent changes the detection angle parameter from conventional 90° to 45°-135° range, which fundamentally alters the light collection geometry. This parameter change enables simultaneous acquisition of multiple scattering signals, increasing measurement throughput without sacrificing particle detection accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from single-angle detection to multi-angle detection by positioning detectors at different angles (45°-135° range). This dimensional expansion in detection space allows parallel measurement of multiple scattering components, significantly improving measurement speed and throughput

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If elastic scattered light is detected along with inelastic scattered light, then signal intensity is increased, but spectral resolution and material identification accuracy deteriorate

Engineering Contradiction:
Improvematerial identification accuracyVSAvoidelastic scattered light interference
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent segments the scattered light detection into multiple angular channels (45°-135° range). By dividing the detection space into different angular sectors, the system can separate elastic scattering (predominant at certain angles) from inelastic scattering (Raman signal), enabling selective detection that improves material identification accuracy while reducing elastic light interference

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the inelastic scattered light signal from the total scattered light by utilizing specific angular detection geometry. By positioning detectors at 45°-135° angles, the system selectively captures Raman scattering while minimizing elastic scattering contamination, effectively separating the desired signal from the interfering background

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If measurement sensitivity is increased to detect smaller particles, then detection limit is improved, but measurement time increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurement speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary concentration of the particle-laden liquid sample before measurement. By pre-concentrating particles in a controlled manner, the system ensures sufficient particle density in the measurement volume, enabling sensitive detection of small particles while maintaining fast throughput through continuous flow measurement

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4621390A1Arrangement and method for measuring particles, in particular microplastic particles, in liquids
Publication Date: 2025.09.24 DECKMA HAMBURG GMBH
  • EP4621390A1 patent drawingFigure 1~2
  • EP4621390A1 patent drawingFigure 3~4
  • EP4621390A1 patent drawingFigure 5~6

AI summary

Arrangement for measuring particles (20) entrained in a liquid, in particular microplastic particles. The arrangement comprises: a measuring channel (14) with an inlet for supplying the liquid; an illumination unit (13) for emitting a measuring beam path (16) that impinges on a measuring volume (19) of the liquid located in the measuring channel (14) and excites at least one particle (20) located in the measuring volume (19) to emit scattered light; a spectrometer (18) for detecting an inelastic scattered light spectrum of the emitted scattered light; detection optics (15) configured to transmit portions (16a, 16b) of the scattered light that impinge on the detection optics (15) along a detection direction to the spectrometer (18); and an evaluation unit (21) for identifying at least one material type of the particle (20) located in the measuring volume (19) on the basis of the scattered light spectrum recorded by the spectrometer (18).According to the invention, the angle between an optical axis of the measuring beam path (16) and the detection direction lies in a range between 45° and 135°. The signal quality is improved by aligning the detection direction relative to the measuring beam path.