HPLC Mobile Phase for Stable Reduced PQQ Quantification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods fail to accurately quantify reduced pyrroloquinoline quinone due to its instability under measurement conditions, and there is a lack of suitable methods for separating and quantifying both oxidized and reduced forms in the presence of interfering substances like ascorbic acid.
Innovation Solution
A high-performance liquid chromatography (HPLC) method using a reversed phase column with a mobile phase comprising 0.050 to 1.5% phosphoric acid and/or hydrochloric acid and 20 to 50% methanol or acetonitrile, maintaining stability of reduced pyrroloquinoline quinone, and enabling separation and quantification of both forms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional HPLC methods are used to analyze pyrroloquinoline quinone, then oxidized PQQ can be detected, but reduced PQQ cannot be accurately quantified due to oxidation by air during measurement
Solution Approach 1:
The patent applies the inert atmosphere principle by using a mobile phase containing phosphoric acid and/or hydrochloric acid with controlled pH (2.0 or lower) to create a chemically inert environment that prevents oxidation of reduced PQQ. The acidic mobile phase suppresses the oxidation reaction by maintaining reduced PQQ in a stable state throughout the HPLC measurement process, enabling accurate quantification without air oxidation interference.
Solution Approach 2:
The patent applies parameter changes by optimizing the mobile phase composition with specific concentrations of phosphoric acid and/or hydrochloric acid (0.050 to 1.5% by mass) and controlling pH to 2.0 or lower. These parameter changes create optimal conditions that stabilize reduced PQQ while maintaining separation efficiency, resolving the contradiction between measurement accuracy and compositional stability.
2Reliability
If ascorbic acid is removed by air oxidation before HPLC analysis, then interference from reducing agents is suppressed, but the analysis time is extended and reduced PQQ may be lost
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the mobile phase to contain phosphoric acid and/or hydrochloric acid at optimized concentrations before analysis begins. This preliminary preparation ensures that reduced PQQ is immediately protected from oxidation upon injection, eliminating the need for time-consuming pre-oxidation steps to remove ascorbic acid while maintaining reliable interference suppression.
Solution Approach 2:
The patent converts the harmful effect of ascorbic acid (reducing agent interference) into a beneficial situation by using the mobile phase conditions to stabilize both ascorbic acid and reduced PQQ in their reduced forms. This allows coexistence of reducing agents and reduced PQQ in the mobile phase without oxidation interference, eliminating the need for removal steps and reducing analysis time.
3Measurement precision
If oxidized PQQ and reduced PQQ are analyzed separately, then each form can be detected, but the analysis procedure becomes complex and time-consuming
Solution Approach 1:
The patent applies universality by developing a single HPLC method with optimized mobile phase conditions that can simultaneously detect and quantify both oxidized PQQ and reduced PQQ. The mobile phase containing phosphoric acid and/or hydrochloric acid at controlled pH serves multiple functions: it stabilizes reduced PQQ, enables separation of both forms, and provides a universal analysis condition for various PQQ-containing samples, simplifying the analytical procedure.
Solution Approach 2:
The patent merges the detection of oxidized PQQ and reduced PQQ into a single analytical run by optimizing the mobile phase to maintain both forms in stable states. The combined analysis approach uses one HPLC method rather than separate procedures, reducing device complexity and analysis time while maintaining measurement precision for both forms.
4Manufacturing precision
If a mobile phase with high organic solvent content is used to improve separation, then resolution increases, but reduced PQQ stability decreases due to increased oxidation
Solution Approach 1:
The patent applies parameter changes by optimizing the balance between organic solvent content (20 to 50% by volume) and acid concentration (0.050 to 1.5% by mass phosphoric acid and/or hydrochloric acid) in the mobile phase. This parameter optimization achieves sufficient separation resolution while maintaining reduced PQQ stability through the acidic environment that suppresses oxidation, even in the presence of organic solvents.
Solution Approach 2:
The patent uses a composite mobile phase composition combining phosphoric acid and/or hydrochloric acid with organic solvents (methanol and/or acetonitrile) in specific ratios. This composite mobile phase provides both the separation power of organic solvents and the stabilization effect of acids, resolving the contradiction between resolution and stability by integrating the beneficial properties of both components.
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 method allows for rapid and accurate quantification of pyrroloquinoline quinone in the presence of interfering substances, facilitating its use in health foods and medicaments by stabilizing reduced pyrroloquinoline quinone and separating oxidized and reduced forms effectively.
Implementation Method 1
separating the reduced pyrroloquinoline quinone or a salt thereof contained in the sample for high performance liquid chromatography from the specimen using interaction between a stationary phase and a mobile phase by a high performance liquid chromatography method
Implementation Method 2
reduced pyrroloquinoline quinone has a problem with the stability under measurement conditions such as oxidation with air
Data Source
AI summary
An object is to provide a high performance liquid chromatography method which enables quantitative analysis with the stability of reduced pyrroloquinoline quinone under measurement conditions maintained. The object can be achieved by the following method. A high performance liquid chromatography analysis method, comprising: a sample preparation step of preparing a sample for high performance liquid chromatography containing reduced pyrroloquinoline quinone or a salt thereof from a specimen and a separation step of separating the reduced pyrroloquinoline quinone or a salt thereof contained in the sample for high performance liquid chromatography from the specimen using interaction between a stationary phase and a mobile phase by a high performance liquid chromatography method using a reversed phase column as the stationary phase and using an eluent comprising 0.050 to 1.5% by mass of phosphoric acid and/or hydrochloric acid and 20 to 50% by volume of methanol and/or acetonitrile as the mobile phase.