Silicone Potassium Ion-Selective Electrode for Undiluted Urine

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Solution Overview

Problem

Current urinalysis devices using PVC-based ion-selective electrodes are not suitable for analyzing undiluted urine, requiring dilution and resulting in inaccurate and unreliable measurements of potassium ions, which delays clinical evaluation, especially in emergency conditions for ICU patients.

Innovation Solution

The development of an ion-selective electrode for potassium ions using a silicone polymer matrix with valinomycin as the ionophore, directly compatible with undiluted urine, and a method for manufacturing this electrode without adhesives, allowing direct contact and accurate measurements, along with an ion-selective electrode for ammonium ions for simultaneous potentiometric measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PVC-based ion-selective electrodes are used for potassium ion analysis, then the electrode structure is stable and manufacturable, but the measurements become inaccurate and unreliable when in contact with undiluted urine

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidcompatibility with undiluted urine
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the chemical composition parameters of the membrane by replacing PVC with a silicone polymer matrix and adjusting the plasticizer ratio (from 20-30% in PVC to 70-80% in silicone). This parameter change enables the membrane to withstand undiluted urine without degradation, resolving the contradiction between measurement reliability and compatibility with undiluted urine.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite membrane material combining silicone polymer, ionophore (valinomycin), and plasticizer (octyl ether). This composite structure provides both the chemical stability needed for reliable measurements and the biocompatibility required for direct contact with undiluted urine, solving the contradiction between reliability and adaptability.

Inventive Principle:
Principle #40Composite materials

2Loss of time

If undiluted urine is analyzed directly, then diagnostic time is reduced and clinical evaluation is accelerated, but measurement accuracy and repeatability deteriorate

Engineering Contradiction:
Improvediagnostic timeVSAvoidanalytical accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent modifies the membrane composition parameters to include high比例的 plasticizer (70-80% of total membrane composition), which increases ion mobility and maintains electrode response linearity in undiluted urine. This enables direct analysis without dilution while preserving measurement precision, resolving the contradiction between diagnostic time and analytical accuracy.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If PVC matrix is used in the membrane, then the membrane structure is stable, but continuous concentration measurement of potassium ions becomes inaccurate

Engineering Contradiction:
Improvemembrane structural stabilityVSAvoidpotassium ion concentration measurement
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent replaces PVC with a silicone polymer-based composite material that incorporates ionophore and plasticizer. This composite provides both structural stability (silicone polymer backbone) and accurate ion measurement capability (ionophore-complex formation), resolving the contradiction between membrane stability and measurement precision.

Inventive Principle:
Principle #40Composite materials

4Measurement precision

If dilution is performed to enable accurate measurement, then measurement accuracy improves, but the complexity of the analysis procedure increases and productivity decreases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidanalysis throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts and eliminates the dilution step from the analysis procedure by designing a membrane specifically optimized for undiluted urine. This removes the time-consuming dilution and mixing operations, directly improving analysis throughput and productivity while maintaining measurement accuracy through the specialized silicone-based membrane composition.

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 solution provides reliable and accurate measurements of potassium and ammonium ions in undiluted urine, extending the linear range and improving reproducibility, enabling timely and precise diagnostic evaluations without the need for dilution, and extending the electrode's useful life by eliminating adhesive-related contamination.

Implementation Method 1

The electrode is commonly equipped with a sensitive part (membrane), which generates a potential difference, due to the different concentration between the reference solution and the one containing the analyte. This potential difference is converted into ion concentration

Methodology Applied
Scientific EffectPotentiometry: Electric Field

Implementation Method 2

The device comprises at least one ion-selective electrode for ammonium ions and an electrode for determining the pH, the simultaneous presence of which in the device allows to have indications relating to the metabolic state

Methodology Applied
Scientific EffectPotentiometry: Electric Field

Implementation Method 3

an electrode for determining the pH

Methodology Applied
Scientific EffectpH measurement: Electric Field

Data Source

PatentEP4027140A1Analysis device for untreated urine
Publication Date: 2022.07.13 RED OAK PERSONAL FINANCIAL LTD
  • EP4027140A1 patent drawingFigure 1~2
  • EP4027140A1 patent drawingFigure 3~4
  • EP4027140A1 patent drawingFigure 5~6

AI summary

It is provided an urine analysis device (1) for analysing an untreated urine sample and determining the physio-chemical characteristics of the urine sample; the analysis device (1) comprising a sampler inlet (2) adapted to be put in a fluid passage connection with a patient and to dose a portion of fluid to be analysed; and an analysis station (3) placed in fluid passage connection with the sampler inlet (2), suitable for carrying out the analysis of at least part of the portion of fluid to be analysed and comprising a plurality of ion-selective electrodes (30) including ion-selective electrode K+ (31) for potassium ions (K+) comprising a support body (310), a first internal reference electrode (311), a reference solution (312) and a selective element (313) comprising a substrate (3133), and a membrane (3130) comprising at least one silicone polymer (3131) and an ionophore polymer ( 3132) and an ion-selective electrode NH4+ (32), and in which the analysis station (3) is configured to correct the measurements of the ion-selective electrode NH4 + (32) by means of a predetermined correction algorithm in such a way as to replicate the accuracy of the ion-selective electrode K+ (31) on the ion-selective electrode NH4+ (32) exclusively by computational calculations.