Passivated SERS Measuring Head for In-Line Raman Sensing
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Solution Overview
Problem
Conventional Raman spectroscopy is limited by low Raman scattered light intensity, making it unsuitable for measuring low concentrations of target analytes, and SERS substrates are fragile, require cavities that are difficult to clean and sterilize, and unsuitable for in-line measurements.
Innovation Solution
A measuring head with a SERS-substrate protected by a chemically inert passivation layer and evanescent coupling, allowing for in-line measurements without cavities, enabling cleaning and sterilization, and preventing molecule adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SERS-substrate is used to enhance Raman scattered light intensity, then measurement sensitivity is improved, but the substrate becomes fragile and requires protective cavities that are difficult to clean and sterilize
Solution Approach 1:
The patent extracts the SERS-substrate from the cavity structure and positions it directly on the exterior surface of the container. This eliminates the need for protective cavities while maintaining the SERS enhancement function, thereby enabling direct cleaning and sterilization of the container surface without removing or damaging the SERS-substrate.
Solution Approach 2:
The patent introduces a transparent window as an intermediary element between the excitation light source and the SERS-substrate. The window allows optical transmission while protecting the SERS-substrate from direct contact with the medium, enabling both measurement functionality and ease of cleaning/sterilization of the container exterior.
2Reliability
If cavity is used to accommodate colloidal material and protect SERS-substrate, then substrate protection is improved, but the cavity is incompatible with in-line measurements and cleaning protocols
Solution Approach 1:
The patent removes the cavity structure entirely and positions the SERS-substrate directly on the container exterior. This extraction eliminates the compatibility issues with in-line measurements and cleaning protocols while maintaining substrate protection through the transparent window and direct mounting configuration.
Solution Approach 2:
Instead of placing the SERS-substrate inside a cavity and accessing it through complex optical paths, the patent inverts the arrangement by positioning the substrate on the exterior surface, allowing direct access for cleaning and sterilization while maintaining the evanescent field coupling for measurements.
3Measurement precision
If molecules are adsorbed on SERS-substrate to enable measurement, then measurement capability is improved, but the adsorption process is exothermic and may destroy molecules or prevent further use of colloidal material
Solution Approach 1:
The patent introduces a transparent window as an intermediary that allows optical coupling for SERS measurements without requiring direct contact between the SERS-substrate and the medium. This intermediary approach enables measurement capability while preventing the exothermic adsorption process that would otherwise occur at the substrate surface, thereby avoiding molecule destruction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous operation without molecule adsorption, supports in-line measurements, and meets hygiene standards through cleaning and sterilization protocols.
Implementation Method 1
refract the received excitation light towards the SERS-substrate such that an evanescent field extends from the evanescently coupled SERS-substrate into the medium adjacent an outside surface of the passivation layer
Implementation Method 2
surface-enhanced Raman spectroscopy (SERS) constitutes a promising alternative to conventional Raman spectroscopy. In SERS, an enhancement of Raman scattered light emitted by molecules of target analytes is achieved by exposing the molecules to an evanescent field emanating from a SERS-substrate
Implementation Method 3
an optical device including a window closing off an opening of the housing and a prism extending into the interior of the housing
Data Source
AI summary
A measuring head and a measurement apparatus comprising a measuring head for performing surface-enhanced Raman spectroscopic measurements. The measuring head comprises a housing, an optical device including a window closing off an opening of the housing and a prism extending into the interior of the housing, and a SERS-substrate disposed on an outer side of the measuring head. The SERS-substrate includes a nanostructured layer and a chemically inert, transparent passivation layer. The optical device is evanescently coupled to the SERS-substrate and configured to receive excitation light transmitted to the optical device through the housing, to refract the excitation light towards the SERS-substrate such that an evanescent field extends from the SERS-substrate into a medium adjacent an outside surface of the passivation layer, and to receive Raman scattered light emanating from the medium through the SERS-substrate and to direct the Raman scattered light through the housing.