Percarboxylic Acid Indicator Solution for Sterilization
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Solution Overview
Problem
Current methods for determining the concentration of percarboxylic acid in aqueous solutions for chemical sterilization or disinfection lack accuracy and sensitivity, particularly in medical settings where precise concentration is crucial for effective disinfection, and existing devices are either expensive or prone to human error in visual determination.
Innovation Solution
A PCAC-determining device using an indicator solution comprising starch, iodide, thiosulfate, and a water-soluble organic solvent, which impregnated into a determination part, allows for clear black color development at effective concentrations and distinct recognition of white spots at sub-effective concentrations, enabling accurate visual determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrochemical sensors are used to measure percarboxylic acid concentration continuously, then measurement precision and productivity are improved, but device complexity and installation cost increase
Solution Approach 1:
The patent extracts the measurement function from complex electrochemical sensors and implements it through a simple visual indicator system. The indicator solution containing starch and iodide provides a straightforward color-based detection method that can be performed with basic laboratory equipment, eliminating the need for sophisticated sensors while maintaining measurement capability.
Solution Approach 2:
The patent replaces electrochemical measurement systems with an optical/visual system. Instead of using electrochemical sensors that require power sources, complex electronics, and trained operators, the invention uses color changes in an indicator solution that can be observed with the naked eye or simple spectrophotometers, significantly simplifying the overall system.
2Ease of operation
If visual determination methods are used for percarboxylic acid concentration, then ease of operation is improved, but measurement precision deteriorates due to human error in color comparison
Solution Approach 1:
The patent utilizes color changes in the indicator solution to provide both ease of operation and improved measurement precision. The indicator solution contains starch and iodide that form a blue-black complex with percarboxylic acid, creating a clear visual distinction between different concentration levels. This color-based approach eliminates subjective human error in comparison while remaining simple to operate.
Solution Approach 2:
The patent changes the detection parameter from subjective visual estimation to objective color intensity measurement. By using an indicator solution that produces distinct color changes at specific concentration thresholds, the system transforms qualitative visual determination into quantitative measurement capability, improving precision while maintaining operational simplicity.
3Ease of manufacture
If existing indicator solutions are used without organic solvents, then manufacturing simplicity is maintained, but measurement precision deteriorates due to poor color development
Solution Approach 1:
The patent creates a composite indicator solution by combining water-soluble organic solvents with starch and iodide. This composite formulation enhances the color development properties of the indicator system, producing sharper and more distinct color changes that improve measurement precision while remaining relatively simple to manufacture.
Solution Approach 2:
The patent modifies the solvent parameters of the indicator solution by incorporating water-soluble organic solvents. This parameter change optimizes the solubility and reactivity of the indicator components, leading to improved color development characteristics and enhanced measurement precision without significantly complicating the manufacturing process.
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 device provides clear and sensitive visual determination of percarboxylic acid concentration, reducing errors and ensuring effective disinfection by distinguishing between effective and ineffective concentrations with high accuracy.
Implementation Method 1
The determination is made using an iodine-starch reaction in which a peroxide of an organic carboxylic acid, such as peracetic acid, iodide ion, and starch are reacted to produce a blue complex.
Data Source
AI summary
The invention provides a percarboxylic acid concentration-determining device capable of determining the concentration of percarboxylic acid contained in an aqueous solution for chemical sterilization or disinfection that contains a percarboxylic acid as an active ingredient; and an indicator solution for use in preparing the device. The indicator solution contains a starch, an iodide, a thiosulfate, a water-soluble organic solvent, and water, with the starch, the iodide, the thiosulfate, and the water-soluble organic solvent being present in the following proportions, based on the total amount taken as 100 mass %: (a) starch: 0.01 to 5 mass %; (b) iodide: 0.01 to 5 mass %; (c) thiosulfate: 0.01 to 10 mass %; and (d) water-soluble organic solvent: 0.1 to 40 mass %, wherein the total amount of (a), (b), and (c) is greater than 0.6 mass %.