UV LED Fluorescence Detection Apparatus for Liquid Chromatography
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Solution Overview
Problem
Current fluorescence detection methods in liquid chromatography are either expensive and sensitive or cost-efficient but less sensitive, lacking a balance between affordability and accuracy.
Innovation Solution
A cost-efficient apparatus using UV LEDs as light sources for absorbance and fluorescence measurement, combined with optical fibers and filters to enhance sensitivity and accuracy, allowing for separate or simultaneous measurement of absorbance and fluorescence using a single or dual light source setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectrometer is used to detect fluorescence signals, then sensitivity and wavelength selection capabilities are improved, but the apparatus becomes expensive and bulky
Solution Approach 1:
The patent divides the detection system into separate functional modules: a simple photodetector for signal detection, optical filters for wavelength selection, and a microcontroller for data processing. This segmentation replaces the need for a complex spectrometer while maintaining fluorescence detection sensitivity through targeted wavelength filtering.
Solution Approach 2:
The patent introduces optical filters as intermediary components between the light source and photodetector. These filters selectively transmit specific wavelengths to enable fluorescence detection without requiring a spectrometer, thus reducing apparatus complexity while preserving measurement precision.
2Device complexity
If fiber-optical probes are used for fluorescence measurement, then apparatus cost is reduced, but measurement sensitivity and accuracy decrease
Solution Approach 1:
The patent replaces the fiber-optical probe mechanical system with a direct optical path using LEDs and optical filters. This substitution maintains low apparatus cost while improving measurement sensitivity by eliminating the signal loss and complexity associated with fiber-optical coupling.
Solution Approach 2:
The patent changes the light source parameter from broad-spectrum (suitable for fiber-optical probes) to specific wavelength LEDs that match the fluorescence excitation requirements. This parameter change enables sensitive fluorescence detection without requiring expensive fiber-optical probe systems.
3Device complexity
If a single light source is used for both absorbance and fluorescence measurement, then device complexity is reduced, but wavelength selection capability is limited
Solution Approach 1:
The patent designs the LED-based light source system to serve multiple functions: the same hardware platform can perform both absorbance measurements (using the LED directly) and fluorescence measurements (using the LED with appropriate optical filters). This multi-functionality reduces device complexity while maintaining wavelength selection capability through software-controlled filter selection.
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 apparatus achieves high sensitivity and accuracy in fluorescence detection while being cost-effective, using UV LEDs and optical filters to isolate and measure absorbance and fluorescence signals effectively.
Implementation Method 1
a first light source (3), preferably a UV LED that emits light suitable for use in measuring the absorbance of a sample
Implementation Method 2
A second light source (4), preferably also a UV LED, is also arranged to irradiate the flow cell (2) and emits light that is suitable for measuring the fluorescence of a sample placed in the flow cell (2)
Implementation Method 3
The light from the first light source (3) is then transmitted to a reference detector (15) through a first additional band pass filter (17) that is configured to allow only a narrow wavelength range
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed is apparatus (1) for measuring fluorescence and absorbance of a substance in a sample, said apparatus (1) comprising: a flow cell (2) for containing a sample, a first light source (3), a first conductor (5) for transmitting light from the first light source (3) to the flow cell (2) for irradiating a sample contained therein, a second conductor (7) for transmitting light from the flow cell (2) to a sample detector (9) arranged to detect an electromagnetic radiation that has passed through said cell (2), and a processing unit (16) arranged to receive a first signal (31) from a reference detector (15) and a second signal (32) from the sample detector (9) and to determine an absorbance based on said first and second signals (31,32), said apparatus (1) further comprising a second light source (4), a third conductor (6) for transmitting light from the second light source (4) to the cell (2) and wherein the sample detector (9) is further arranged to also detect fluorescence signals in the light that has passed through the flow cell (2). The invention also relates to a method for measuring the absorbance and the fluorescence of a substance in a sample.