Fluorescence Detector Temperature Control for Liquid Chromatography
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Solution Overview
Problem
Fluorescence detectors in liquid chromatographs face challenges in achieving reproducible results due to temperature-dependent fluorescence emission from samples and photodetector sensitivity, leading to errors and increased production costs from requiring temperature-stable photodetectors.
Innovation Solution
A fluorescence detector design incorporating a sample temperature control block, a photodetector temperature control block, and a unified temperature control system using a Peltier device or cooling cycle to maintain both the sample and photodetector at constant temperatures, enhancing thermal conductivity and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photodetector with weak temperature dependence is selected to reduce measurement error, then measurement precision is improved, but device complexity and production cost increase due to limited photodetector choices
Solution Approach 1:
The patent changes the temperature parameter of the photodetector by introducing a temperature control system that actively regulates the photodetector's temperature, thereby compensating for temperature-dependent sensitivity variations without requiring specialized low-temperature-coefficient photodetectors
Solution Approach 2:
The patent replaces the mechanical selection of temperature-stable photodetectors with a thermal control system that actively manages temperature, substituting a passive component selection approach with an active control mechanism
2Measurement precision
If the temperature of the detector is increased to improve photodetector performance, then sensitivity is improved, but noise increases due to increased dark current
Solution Approach 1:
The patent optimizes the temperature parameter by maintaining it at a constant moderate level rather than increasing it, using active temperature control to prevent temperature-induced dark current increases while preserving photodetector sensitivity through proper thermal management
Solution Approach 2:
The patent implements a feedback control system that continuously monitors and adjusts the photodetector temperature to maintain it at an optimal setpoint, preventing temperature excursions that would increase dark current while ensuring sufficient sensitivity
3Measurement precision
If only sample temperature control is implemented to reduce fluorescence emission error, then measurement precision is improved, but device complexity is reduced, however photodetector temperature variations still cause measurement errors
Solution Approach 1:
The patent merges the sample temperature control and photodetector temperature control into a unified system where both temperatures are regulated by a common control architecture, allowing coordinated temperature management that addresses both fluorescence emission stability and photodetector sensitivity stability
Solution Approach 2:
The patent creates a universal temperature control system that serves multiple functions: controlling sample temperature to stabilize fluorescence emission and controlling photodetector temperature to stabilize sensitivity, thereby reducing overall system complexity through functional integration
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
This design improves the reproducibility of detection results by minimizing the impact of ambient temperature on fluorescence emission and photodetector sensitivity, reducing production costs without the need for temperature-stable photodetectors.
Implementation Method 1
a temperature control system constituted from a Peltier device provided in the vicinity of the heat exchanging portion
Implementation Method 2
a heat exchanging portion provided upstream of a flow cell on a flow passage for flowing a sample
Implementation Method 3
the amount of fluorescence emitted from the excited sample is measured by a photodetector
Data Source
AI summary
The fluorescence detector includes: a flow cell provided on a flow passage for flowing a sample; a sample temperature control block for keeping the flow cell and the flow passage located on the sample inlet side of the flow cell at a constant temperature; an excitation optical system; a fluorescence optical system having a photodetector and used for guiding fluorescence emitted from a sample flowing through the flow cell to the photodetector and detecting the fluorescence; a photodetector temperature control block for keeping the photodetector at a constant temperature; and a temperature control unit having a simultaneous temperature control block united with both the temperature control blocks and a temperature control system provided to be in contact with the simultaneous temperature control block to heat and/or cool the simultaneous temperature control block.