Liquid Chromatograph pH Measurement via Flow Path Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Accurate measurement of the pH of a mobile phase in liquid chromatography is challenging without interfering with the analysis of the sample, as existing methods often damage pH meters or contaminate the sample with electrolyte solutions.
Innovation Solution
A liquid chromatograph configuration with a flow path switch valve and a pH meter in a low-pressure flow path allows for separate measurement of the pH of the aqueous solvent without mixing it with the sample, preventing damage to the pH meter and contamination of the sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pH meter is provided in the mobile phase flow path to measure pH accurately, then measurement precision is improved, but the pH meter may be damaged by high pressure and the sample may be contaminated with electrolyte solutions
Solution Approach 1:
The flow path is divided into two separate paths: a first flow path for pH measurement and a second flow path for sample analysis. The pH meter is placed only in the first flow path, isolating it from the high-pressure sample flow path, thus preventing damage to the pH meter and contamination of the sample while maintaining accurate pH measurement capability
Solution Approach 2:
A flow path switch valve acts as an intermediary device that directs the mobile phase flow between the first flow path (for pH measurement) and the second flow path (for sample analysis). This intermediary mechanism allows the pH meter to measure pH accurately without being exposed to high pressure or sample contamination, while still enabling pH-based analysis of the sample
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 accurate pH measurement of the mobile phase without interfering with the sample analysis, protecting the pH meter from high pressures and preventing protein adhesion, thus ensuring reliable chromatographic results.
Implementation Method 1
a pH meter that is provided in the first flow path and measures a pH of the aqueous solvent flowing through the first flow path
Implementation Method 2
The sample that has been introduced into the column is eluted into compounds based on a difference in chemical property or composition
Data Source
AI summary
When a flow path switch valve is in a first flow path state, an aqueous solvent supplied by an aqueous solvent supplier is guided to a first flow path, and a pH of the aqueous solvent is measured by a pH meter provided in the first flow path. When the flow path switch valve is in a second flow path state, the aqueous solvent supplied by the aqueous solvent supplier is guided to a second flow path. A sample to be analyzed is supplied by a sample supplier at a position farther downstream than the flow path switch valve. The solvent that has passed through the second flow path and the sample supplied by the sample supplier are guided to a separation column. The sample that has passed through the separation column is detected by a detector.