Azo Compound Analysis via LC-MS Gradient Elution
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Solution Overview
Problem
Current methods for quantitatively analyzing azo compounds in fiber products and other samples are inefficient due to low detection sensitivity and interference from foreign substances, leading to increased testing time and cost, which hinders the export of fiber products and compliance with stringent regulations.
Innovation Solution
A method utilizing liquid chromatography coupled with mass spectrometry, employing gradient analyses with specific mobile phases such as aqueous ammonium acetate or ammonium formate solutions and organic solvents, to efficiently detect and quantify a wide range of azo compounds, including those banned or regulated by the EU, with improved sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional analyzing techniques (GC, LC, GC-MS, LC-MS) are used to detect azo compounds, then the analysis can be performed, but the detection sensitivity is low and foreign substances interfere with the results
Solution Approach 1:
The patent changes the chemical parameters of the mobile phase by using ammonium acetate or ammonium formate buffers at specific pH values (3.5-4.5), which improves the ionization efficiency of azo compounds in the mass spectrometer, thereby enhancing detection sensitivity and reducing interference from foreign substances
Solution Approach 2:
The patent introduces ammonium acetate or ammonium formate as an intermediary substance in the mobile phase, which facilitates the ionization of azo compounds and improves their detectability by the mass spectrometer while minimizing interference from other substances in the sample
2Measurement precision
If different analyzing devices or analysis conditions are changed for each compound to avoid low sensitivity and foreign substance interference, then the analysis accuracy improves, but the analysis time becomes excessively long
Solution Approach 1:
The patent develops a universal liquid chromatography-mass spectrometry method that can simultaneously analyze multiple different azo compounds using a single set of optimized conditions, eliminating the need to switch between different devices or analysis conditions for each compound while maintaining high accuracy
Solution Approach 2:
The patent combines the detection of multiple azo compounds into a single analysis run by optimizing the liquid chromatography separation conditions and mass spectrometry detection parameters, thereby reducing the total analysis time while maintaining high measurement precision for all target compounds
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
This approach enables efficient and accurate analysis of multiple azo compounds, reducing testing time and costs, and ensuring compliance with regulatory standards by enhancing detection sensitivity and minimizing interference from foreign substances.
Implementation Method 1
a first analyzing step in which a first analysis is performed for a target sample to detect a plurality of azo compounds in the sample, using a liquid chromatograph
Implementation Method 2
the liquid chromatograph being coupled with a mass spectrometer
Data Source
AI summary
A large number of kinds of azo compounds which are representative hazardous substances in fiber products are divided into two groups. The compounds included in the first group are detected by an MRM measurement by a tandem mass spectrometer unit (12) in a measurement section (10) while a two-liquid gradient elution under an acidic condition is performed in a liquid chromatograph unit (11), using an aqueous ammonium acetate solution as mobile phase A, and a mixture of acetonitrile and an aqueous ammonium acetate solution as mobile phase B. On the other hand, the compounds included in the second group are detected by an MRM measurement while a two-liquid gradient elution under a neutral or weakly basic condition is performed using an aqueous ammonium bicarbonate solution as mobile phase A and acetonitrile as mobile phase B. An exhaustive quantitative analysis for major azo compounds can be achieved by performing the two analyses for the same sample. An efficient test with a shortened analysis period can thereby be performed.