Dry Test Strip Calcium Measurement Magnesium Masking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dry test strips for measuring calcium using the OCPC method suffer from large measurement errors due to magnesium interference and reagent degradation over time, leading to inaccurate results.
Innovation Solution
Incorporating a magnesium selective masking agent, such as 8-hydroxyquinoline, and a pH buffer like N-cyclohexyl-3-aminopropanesulfonic acid and N-methyl-D-glucamine to adjust the reaction pH to 10.0-11.0, along with a surfactant like p-t-octyl phenol polyoxyethylene, in the dry test strip to minimize measurement errors and reagent degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dry test strip uses the OCPC method with alkaline buffer (pH 9.2) for calcium measurement, then the measurement can be performed rapidly and conveniently, but large measurement errors occur due to magnesium interference
Solution Approach 1:
A magnesium-selective masking agent (8-hydroxyquinoline) is introduced as an intermediary substance that selectively binds to magnesium ions, preventing them from interfering with the calcium measurement. The masking agent acts as a mediator that removes the harmful magnesium interference while allowing the calcium-OCPC reaction to proceed accurately, thus resolving the contradiction between rapid measurement and measurement precision.
Solution Approach 2:
The pH buffer system is changed from conventional alkaline buffer (pH 9.2) to a specific pH range (10.0-11.0) using N-cyclohexyl-3-aminopropanesulfonic acid and N-methyl-D-glucamine. This parameter change optimizes the reaction conditions for the OCPC method while enhancing the effectiveness of the magnesium masking agent, thereby improving measurement accuracy without sacrificing measurement speed.
2Duration of action of stationary object
If the dry test strip is stored for a long time, then it can be used for extended periods, but the reagent degrades due to deliquescent nature causing large measurement errors
Solution Approach 1:
The patent employs a disposable dry test strip design where the reagent layer contains stabilizers that maintain reagent integrity during storage. The strip is designed for single-use, eliminating the need for long-term reagent stability while ensuring high measurement reliability during its intended storage period. This approach resolves the contradiction by accepting limited storage duration in exchange for maintaining reliable measurements throughout the storage period.
Solution Approach 2:
The harmful deliquescent properties of the reagent are effectively removed or neutralized by extracting the problematic components and replacing them with stable alternative reagents and stabilizers. This extraction of the degradation mechanism allows the test strip to maintain reagent stability throughout its storage life, ensuring consistent measurement reliability.
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 significantly reduces measurement errors by selectively masking magnesium and maintaining reagent stability, providing precise calcium detection with improved accuracy and reliability over time.
Implementation Method 1
a magnesium selective masking agent
Implementation Method 2
a pH buffer for adjusting the pH of the environment for reaction of the o-cresolphthalene complexone with calcium to 10.0-11.0
Implementation Method 3
calcium is allowed to chelate with o-cresolphthalene complexone (OCPC) under alkaline conditions
Implementation Method 4
the substance reacts with the reagent contained in the reagent layer to generate color
Implementation Method 5
the dry test strip for measuring calcium further contains a surfactant
Data Source
AI summary
A dry test strip for measuring calcium is comprising a support, a reagent layer provided on the support, and a reagent holding layer provided on the reagent layer, and containing, as reagents, o-cresolphthalene complexone, a magnesium selective masking agent, and a pH buffer for adjusting the pH of the environment for reaction of the o-cresolphthalene complexone with calcium to 10.0-11.0, wherein such reagents are present in either the reagent layer or the reagent holding layer or the both layers.