Boron-Doped Diamond pH Electrode for Low Conductivity Samples
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Solution Overview
Problem
Conventional pH electrodes are fragile, prone to breakage, and suffer from 'alkali errors due to interfering ions, making them costly to maintain and less suitable for low conductivity samples like drinking water, which requires accurate and robust pH measurement.
Innovation Solution
A single pit boron-doped diamond (BDD) electrode with a laser-machined sp2 carbon region, integrated into a boron-doped diamond-based pH sensor, providing improved accuracy and resistance to fouling from particulates, and capable of measuring pH across a wide range without the need for frequent calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pH electrodes are used, then pH measurement is achieved, but the electrodes are fragile and require frequent maintenance and calibration
Solution Approach 1:
The patent changes the material parameter of the electrode from conventional glass or metal to boron-doped diamond, which fundamentally alters the mechanical and chemical properties. This material substitution provides exceptional hardness, chemical inertness, and electrochemical stability, eliminating the fragility and maintenance issues of conventional electrodes while maintaining pH measurement functionality
Solution Approach 2:
The patent employs a composite structure combining boron-doped diamond material with specific surface treatments and geometric configurations. The BDD substrate provides mechanical robustness and chemical stability, while surface modifications enable pH-sensitive electrochemical responses, creating a composite system that overcomes the limitations of single-material conventional electrodes
2Measurement precision
If conventional pH electrodes are used, then pH measurement is achieved, but they suffer from alkali errors due to interfering ions
Solution Approach 1:
The patent changes the electrochemical parameters of the electrode by using boron-doped diamond with specific doping concentrations and surface treatments. This creates an electrode surface that is insensitive to alkali metal ions while maintaining sensitivity to hydrogen ions, thereby eliminating alkali errors and improving measurement precision in samples containing interfering ions
Solution Approach 2:
The patent converts the chemical inertness of boron-doped diamond, which might seem to reduce reactivity, into a benefit by creating a surface that selectively responds only to hydrogen ions. The electrochemically inactive surface toward interfering ions transforms potential measurement errors into measurement accuracy, as the electrode ignores harmful interfering species while detecting the target analyte
3Measurement precision
If conventional pH electrodes are used, then pH measurement is achieved, but they require frequent calibration
Solution Approach 1:
The boron-doped diamond electrode exhibits self-stabilizing properties where the electrochemical surface groups automatically maintain their protonation state in response to pH changes without drifting. This self-regulating behavior eliminates the need for frequent manual calibration, as the electrode maintains measurement precision automatically over extended periods
Solution Approach 2:
The patent creates an electrode with excessive chemical stability and electrochemical robustness beyond what is minimally required. This over-engineered stability ensures that the electrode maintains calibration across a wide range of operating conditions and time periods, making frequent calibration unnecessary while preserving measurement accuracy
4Adaptability or versatility
If conventional pH electrodes are used, then pH measurement is achieved, but they are not suitable for low conductivity samples
Solution Approach 1:
The patent changes the electrical parameters of the electrode by using boron-doped diamond with optimized doping levels and surface conductivity. This creates an electrode with low background current and high signal-to-noise ratio, enabling reliable pH measurement in low conductivity samples where conventional electrodes fail due to insufficient ionic conductivity
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 single pit BDD electrode offers enhanced accuracy and reduced maintenance costs by minimizing fouling and calibration needs, while maintaining precise pH measurement in low conductivity samples, including environmentally relevant pH ranges.
Implementation Method 1
an electrochemical sensor comprising a boron doped diamond electrode formed of boron doped diamond material; an array of non-diamond carbon sites disposed on a sensing surface of the boron doped diamond electrode
Implementation Method 2
electrochemically active surface groups bonded to the non-diamond carbon sites for generating a redox peak associated with a target species which reacts with the electrochemically active surface groups
Data Source
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AI summary
An embodiment provides a device for measuring pH in an aqueous sample, including: at least one measurement electrode (400) comprising a first carbon region, wherein the carbon region comprises a single pH sensitive carbon region, wherein the single pH sensitive carbon region of the measurement electrode is a sp2 carbon region (402) of a boron doped diamond-based pH electrode (401); at least one reference electrode; at least one auxiliary electrode; and a memory storing instructions executable by a processor to identify a pH of an aqueous sample by measuring an electrical potential between the at least one measurement electrode and the at least one reference electrode. Corresponding pH measurement method as well as corresponding pH measurement system are also disclosed and claimed.