Microring Resonator Array for Liquid Chromatography Refractive Index Detection
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Solution Overview
Problem
Refractive index detectors in liquid chromatography face limitations such as inability to perform gradient separations and extended equilibration times due to the need for a reference cell, resulting in limited sensitivity and dynamic range, which restricts their use to specialty applications.
Innovation Solution
A liquid chromatography system incorporating a microring resonator array that allows for the measurement of bulk refractive index without a reference flow cell, enabling gradient separations and operation under ambient conditions, thus overcoming the limitations of traditional refractive index detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference flow cell is used in traditional refractive index detection, then measurement precision can be improved, but device complexity increases and loss of time occurs due to thermal equilibration requirements
Solution Approach 1:
The patent removes the reference flow cell from the detector system entirely. Instead of using a differential measurement approach with sample and reference cells, the invention uses a single flow cell where the micro-ring resonator directly measures refractive index changes of the mobile phase and analytes, eliminating the need for thermal equilibration between reference and sample cells
Solution Approach 2:
The patent introduces a micro-ring resonator as an intermediary sensing element that couples light to the mobile phase in the flow cell. The resonator's resonant wavelength shifts in response to refractive index changes, providing a sensitive measurement mechanism without requiring the complex reference cell architecture
2Measurement precision
If a reference flow cell with thermal equilibration is used, then measurement precision is improved, but loss of time increases due to extended equilibration periods
Solution Approach 1:
The patent removes the reference flow cell from the detector system entirely. Instead of using a differential measurement approach with sample and reference cells, the invention uses a single flow cell where the micro-ring resonator directly measures refractive index changes of the mobile phase and analytes, eliminating the need for thermal equilibration between reference and sample cells
Solution Approach 2:
The patent enables continuous operation by eliminating the thermal equilibration step. The micro-ring resonator can rapidly track refractive index changes in real-time as the mobile phase flows through the single flow cell, allowing immediate detection without waiting for thermal equilibrium between reference and sample cells
3Adaptability or versatility
If traditional refractive index detection with reference cell is used, then universal detection capability is achieved, but productivity decreases due to limited dynamic range and sensitivity
Solution Approach 1:
The patent changes the detection parameter from direct refractive index measurement to resonant wavelength shift measurement. The micro-ring resonator translates small refractive index changes into larger, more easily measurable wavelength shifts, significantly improving sensitivity and dynamic range while maintaining universal detection capability
Solution Approach 2:
The patent replaces the mechanical/differential measurement system (comparing sample and reference cells) with an optical resonance-based measurement system. The micro-ring resonator provides a more sensitive and rapid detection mechanism that eliminates the limitations of traditional differential refractometry
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
The microring resonator array provides a wide dynamic range and eliminates the need for thermal equilibration, enabling gradient separations and improving sensitivity, making it suitable for a broader range of applications beyond specialty uses.
Implementation Method 1
The detector comprises a microring resonator array
Implementation Method 2
measuring a bulk refractive index of the mobile phase and the one or more components
Data Source
AI summary
A liquid chromatograph comprising a column coupled to a microring resonator array and methods of using the same are disclosed. The microring resonator array measures the bulk refractive index of the mobile phase and any sample injected onto and separated in the column. While carrying out the methods, the composition of a mobile phase passing through the chromatography column may remain substantially constant (isocratic elution) or it may vary (gradient elution). One or more microrings may comprise a covering to act as a thermal control. In addition, the sensor surface may be modified with some type of capture agent that can interact with one or more components in the sample.