Gamma-Stable Reference Gel for Pressure-Resistant pH Sensors
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Solution Overview
Problem
pH sensors with liquid reference electrolytes experience response fluctuations due to pressure sensitivity, leading to measurement errors, especially in pharmaceutical applications where process pressures can vary significantly, and traditional viscous gels are not gamma irradiation stable, making them unsuitable for sterilization.
Innovation Solution
A biocompatible, gamma irradiation stable reference gel composed of water, a reference electrolyte salt, a buffering system, and a polymeric gelling agent like polyethylene glycol, which maintains viscosity and pH stability under irradiation, reducing or eliminating pressure sensitivity without requiring internal pressure in the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a liquid reference electrolyte is used in the reference electrode, then the sensor can be manufactured with simple structure, but the sensor exhibits pressure sensitivity causing response fluctuations under process pressure
Solution Approach 1:
The patent changes the physical state parameter of the reference electrolyte from liquid to gel, transforming it into a semi-solid material that maintains its structure under pressure while still allowing ion transport. This parameter change eliminates pressure-induced response fluctuations without complicating the sensor design.
Solution Approach 2:
The patent uses a composite gel material formed by combining liquid reference electrolyte with a gelling agent (such as silica, cellulose, or polysaccharides). This composite structure provides both the electrochemical properties of the liquid electrolyte and the pressure resistance of the gel matrix, resolving the contradiction between simplicity and stability.
2Stress or pressure
If a highly viscous reference electrolyte gel is used to reduce pressure sensitivity, then the minimum required internal pressure is reduced, but traditional gels degrade under gamma irradiation
Solution Approach 1:
The patent changes the chemical composition parameter of the gelling agent to be gamma irradiation stable. By selecting specific materials like silica, cellulose, or polysaccharides that maintain their gel structure under radiation, the patent eliminates degradation while maintaining the pressure-resistant properties of the gel.
Solution Approach 2:
The patent develops a single-use sensor design where the gel reference electrolyte is intended for disposable application. The gel formulation is specifically designed to withstand gamma irradiation during sterilization and then maintain its properties during the sensor's short operational life, eliminating the need for long-term stability under radiation.
3Reliability
If traditional viscous gels are used as reference electrolyte, then pressure sensitivity is reduced, but the gels undergo gel breakdown and pH changes under gamma irradiation
Solution Approach 1:
The patent changes the chemical composition of the gel system by selecting specific gelling agents (silica, cellulose, polysaccharides) that are resistant to gamma irradiation-induced breakdown. This parameter change ensures that both viscosity and pH remain stable under radiation conditions while maintaining pressure response stability.
Solution Approach 2:
The patent creates a composite gel system combining radiation-stable gelling agents with reference electrolyte salts and buffering systems. This composite formulation maintains structural integrity and chemical stability under gamma irradiation, preventing the gel breakdown and pH changes that occur with traditional gel formulations.
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 gel significantly reduces or eliminates sensor response fluctuations under varying process pressures and maintains stability after gamma irradiation, making it suitable for single-use pharmaceutical pH sensors without the need for internal pressure adjustments.
Implementation Method 1
the gel does not degrade under gamma irradiation
Implementation Method 2
a polymeric gelling agent... the gel does not degrade under gamma irradiation
Implementation Method 3
disturbed ion diffusion from the reference electrode into the process through the reference junction
Implementation Method 4
reference electrolyte... ion diffusion
Implementation Method 5
a buffering system for adjusting pH of the gel... maintains stability after gamma irradiation
Data Source
AI summary
A gel for use in a pH or an ORP sensor, components of the gel comprising water, a reference electrolyte salt, a buffering system for adjusting pH of the gel, and a polymeric gelling agent, and the gel does not degrade under gamma irradiation.