Solid-State pH Sensing for Stable Continuous Flow Measurement
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Solution Overview
Problem
Conventional pH sensors, particularly glass bulb probes, are unreliable and require frequent recalibration due to flow dependence, ionization effects, and structural issues under continuous flow conditions, leading to inaccurate and unstable pH measurements.
Innovation Solution
A continuous flow system with solid state pH sensors, including a redox active material and a pseudo-reference electrode, that are covalently bound to a polymer backbone, providing stable pH measurement without the need for calibration and resistant to flow rate variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional glass bulb pH probes are used in continuous flow conditions, then pH measurement can be performed, but the measurements are flow-dependent and require frequent recalibration
Solution Approach 1:
The patent replaces the mechanical glass bulb probe system with a solid-state electrochemical sensor system. The solid state pH sensor uses a polymer membrane containing pH-sensitive dyes or fluorescent probes instead of glass glass bulbs, eliminating the mechanical fragility and flow-dependence issues of conventional probes while maintaining pH measurement capability
Solution Approach 2:
The patent changes the physical and chemical parameters of the sensing element by using solid-state materials with different properties than glass. The polymer membrane sensors have different ion-selective properties and response characteristics that make them independent of flow rate, thereby improving both measurement precision and reliability in continuous flow conditions
2Measurement precision
If glass membrane pH sensors are used, then pH measurement is possible, but the glass membrane becomes less sensitive to ions over time
Solution Approach 1:
The patent employs disposable solid-state pH sensors that can be easily replaced rather than attempting to maintain long-term stability of the sensing element. The solid state sensors with polymer membranes have longer operational lifespans than glass probes in continuous flow applications, and when degradation occurs, the entire sensor assembly can be quickly replaced without complex maintenance procedures
Solution Approach 2:
The patent uses composite polymer materials containing pH-sensitive dyes, fluorescent probes, or ion-selective components embedded in a polymer matrix. These composite solid-state structures provide enhanced stability and longevity compared to pure glass membranes, maintaining ion sensitivity over extended periods in continuous flow conditions
3Reliability
If conventional reference electrodes with porous frit are used, then reference potential is provided, but the frit clogs and requires storage in KCl solution
Solution Approach 1:
The patent extracts and removes the problematic porous frit component from the reference electrode design. Instead of using a porous frit junction that is prone to clogging, the invention employs alternative reference electrode configurations such as solid-state reference electrodes or reference electrodes with different junction designs that eliminate the frit clogging issue entirely
Solution Approach 2:
The patent implements reference electrode systems that are self-maintaining and do not require external storage solutions like KCl. The solid state reference electrodes or alternative designs provide stable reference potential without requiring the electrode to be stored in specific solutions between uses, thereby eliminating maintenance requirements and improving ease of operation
4Reliability
If high salt concentration electrolyte is used in reference electrode, then reference potential is stable, but salt precipitation clogs the aperture
Solution Approach 1:
The patent converts the harmful effect of salt precipitation into a beneficial design constraint by eliminating the need for high salt concentration electrolyte in the sensing environment. The solid state pH sensors and alternative reference electrode designs function with lower ionic strength solutions or without traditional electrolyte bridges, thereby preventing salt precipitation while maintaining reference potential stability
Solution Approach 2:
The patent changes the ionic strength parameter of the electrolyte environment from high salt concentration to lower concentrations. The solid state sensing mechanism allows operation with reduced ionic strength, eliminating the salt precipitation problem while maintaining sufficient reference potential stability for accurate pH measurement
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 system achieves accurate pH measurements within ±0.1 units over extended periods, maintaining stability and reducing contamination risks, suitable for high-pressure and high-temperature environments.
Implementation Method 1
solid state pH sensors having an analyte sensitive material covalently bound to a polymer backbone
Implementation Method 2
A continuous flow system with solid state pH sensors, including a redox active material and a pseudo-reference electrode
Data Source
AI summary
The present invention relates generally to systems for measuring pH. In particular, the present invention relates to a continuous flow system having one or more solid state pH sensors positioned within a fluid pathway of the system to provide continuous pH measurement.