Karl Fischer Titrator Back Titration Control

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Solution Overview

Problem

Conventional Karl Fischer titration apparatuses are limited in performing precise coulometric back titration and titer determination, as the calculated water content does not match theoretical values, and they lack the capability for back titration due to the absence of necessary components like a burette and injection nozzle, restricting their functionality.

Innovation Solution

A Karl Fischer titration apparatus equipped with a titration flask, injection nozzle, electrolytic electrodes, detection electrode, reference electrode, burette control unit, electrolysis control unit, and calculation unit, allowing for the transition from volumetric titration to coulometric back titration using potential control, enabling accurate water content calculation based on reagent amount and electricity consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If volumetric titration is performed with Karl Fischer reagent, then water content can be measured, but the reagent cannot be reused for titer determination and back titration is limited

Engineering Contradiction:
Improvetitration method versatilityVSAvoidKarl Fischer reagent usability
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent enables recovery and reuse of Karl Fischer reagent through coulometric back titration. After volumetric titration consumes the reagent, the generated iodine is converted back to iodine ions via electrolysis, restoring the reagent to its original state for repeated use in titer determination and subsequent measurements.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The apparatus integrates multiple titration methods (volumetric, coulometric, and back titration) into a single system. The same Karl Fischer reagent can be used for initial titration, then regenerated for titer determination, and the system can switch between different measurement modes, making the apparatus universally applicable for various water content measurement scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If coulometric titration is performed, then precise water content measurement is achieved, but back titration and titer determination cannot be performed due to missing components

Engineering Contradiction:
Improvewater content measurement precisionVSAvoidback titration capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent combines volumetric titration components (burette, injection nozzle) with coulometric titration components (electrolytic electrodes) into a single integrated apparatus. This merger enables the system to perform both volumetric and coulometric methods, including back titration and titer determination, within one device, achieving both precision and versatility.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If current control method is used in coulometric titration, then theoretical values are well-matched, but potential drift occurs and precision deteriorates

Engineering Contradiction:
Improvetheoretical value matchingVSAvoidwater content measurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic switching between current control and potential control methods based on the titration stage. During main titration, current control ensures theoretical accuracy; during back titration and endpoint detection, potential control with real-time potential monitoring eliminates drift effects, maintaining precision throughout the entire measurement process.

Inventive Principle:
Principle #15Dynamics

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

Enables precise coulometric back titration and titer determination, ensuring the produced iodine ions match the applied quantity of electricity, overcoming the limitations of conventional methods and allowing for high-precision water content measurement without the need for standard water-methanol.

Implementation Method 1

a detection electrode 80 for detecting a polarization state

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

the electrolytic treatment is carried out at the electrolytic electrode 95 to produce the iodine from the iodine ions

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP2995940B1Karl fischer titrator and karl fischer titration method
Publication Date: 2017.06.14 KYOTO ELECTRON MFG CO LTD
  • EP2995940B1 patent drawingFigure 1
  • EP2995940B1 patent drawingFigure 2
  • EP2995940B1 patent drawingFigure 3

AI summary

In the invention, a back titration and titer determination can be made using a back coulometric titration. When the iodine exists in a solution put in the titration flask with electrolytic electrodes, a back coulometric titration is performed to produce iodine ions from the iodine at the anode of the electrolytic electrodes. Where the solution is a dehydrated solvent including a Karl Fischer reagent for a volumetric titration, the titer can be determined by the back coulometric titration. Where the solution is anolyte in which the iodine remains after the coulometric titration in the coulometric titration method, the water content in the sample is found from the quantity of electricity consumed by the coulometric titration and the quantity of electricity consumed by the back coulometric titration. Where the solution is anolyte in which the iodine remains by adding Karl Fischer reagent in the volumetric titration method, the water in the sample put in the titration flask is found from the added amount of Karl Fischer reagent and the quantity of electricity consumed by the back coulometric titration.