Microfluidic Formaldehyde Detection via Co-elution

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Solution Overview

Problem

Existing devices for detecting gaseous formaldehyde are limited by irreversibility, discontinuity, high reagent consumption, and the need for additional substances, which hinders precise and efficient analysis, especially in indoor and workplace environments where formaldehyde concentrations are significant.

Innovation Solution

A microfluidic device that co-elutes a gas phase containing formaldehyde with a solution comprising a derivative agent in a capillary tube, utilizing thermoregulation and annular flow to enhance trapping efficiency and sensitivity, allowing for real-time detection with reduced reagent consumption and without additional calibration substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a trapping cell with adsorbent surface is used for formaldehyde detection, then selectivity and sensitivity are improved, but the method becomes irreversible and discontinuous

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

Solution Approach 1:

The invention extracts the formaldehyde trapping function from a separate adsorbent-based trapping cell and integrates it directly into the detection flow cell. The derivative agent solution contacts the gas phase containing formaldehyde directly in the flow cell, eliminating the need for a separate trapping step and enabling continuous measurement while maintaining high sensitivity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the trapping and detection functions into a single integrated flow cell. The derivative agent solution both traps formaldehyde from the gas phase and serves as the detection medium, combining two previously separate steps into one continuous process.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If conventional transfer means with microporous tubes are used, then formaldehyde transfer to aqueous solution is achieved, but the tubes become obstructed by plugging

Engineering Contradiction:
Improvetransfer functionalityVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention removes the microporous tube component entirely from the system. Instead of using a microporous tube for gas-liquid transfer, the device uses direct contact between the gas phase and derivative agent solution in the flow cell, eliminating the plugging issue associated with microporous tubes.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If high reagent consumption rates are used for detection, then detection sensitivity is maintained, but reagent cost and consumption increase to 1 mL/min

Engineering Contradiction:
Improvedetection sensitivityVSAvoidreagent consumption
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The invention changes the operational parameters of the detection system by using a flow cell design that allows for lower flow rates while maintaining detection sensitivity. The direct contact between gas phase and derivative agent solution in the flow cell enhances mass transfer efficiency, enabling sensitive detection at reduced reagent consumption rates.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If additional calibration substances are used in the detection process, then measurement accuracy is improved, but device complexity and operational steps increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention removes the calibration substance injection system from the device. The method uses direct reaction between the derivative agent and formaldehyde in the gas phase, with detection based on the formed derivative compound, eliminating the need for separate calibration substance handling and injection components.

Inventive Principle:
Principle #2Taking out (Extraction)

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 device achieves reliable, precise, and sensitive detection of formaldehyde with reduced reagent use and faster analysis times, improving temporal resolution and autonomy, capable of performing nearly 500 analyses with 10 mL of reagents, while maintaining high sensitivity and precision.

Implementation Method 1

utilizing thermoregulation and annular flow to enhance trapping efficiency and sensitivity

Methodology Applied
Scientific EffectAnnular flow: Two-Phase Flow

Implementation Method 2

mixing means for co-eluting in a capillary tube a gas phase comprising said gaseous compound and a solution comprising a derivative agent

Methodology Applied
Scientific EffectCo-elution: Chromatography

Implementation Method 3

means for eliminating the gas phase

Methodology Applied
Scientific EffectPhase separation: Semipermeable Membrane

Implementation Method 4

means for determining the concentration of gaseous compound

Methodology Applied
Scientific EffectFluorescence spectroscopy: Fluorescence

Implementation Method 5

detectable, via a fluorescence cell, by fluorescence spectroscopy

Methodology Applied
Scientific EffectColorimetry: Absorption Spectroscopy

Data Source

PatentEP3094405B1Microfluidic device for analysis of pollutants in circulation
Publication Date: 2019.12.18 CENT NAT DE LA RECH SCI (C N R S)
  • EP3094405B1 patent drawingFigure 1~3
  • EP3094405B1 patent drawingFigure 4~5

AI summary

The present invention relates to a microfluidic device for analysis of a gaseous compound, in a dynamic manner and while flowing, said device comprising mixing means that make it possible to co-elute, in a capillary tube, a gaseous phase comprising said gaseous compound and a solution comprising a derivative agent; means for eliminating the gaseous phase; and means for determining the concentration of gaseous compound. The present invention also relates to a process for determining the concentration of a gaseous compound using the microfluidic device according to the present invention.