NMR TMAO Quantification Using pH-Stable Reference Peaks
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Solution Overview
Problem
Current methods for determining trimethylamine-N-oxide (TMAO) levels in biosamples, such as human urine and blood plasma, are inefficient due to overlapping peaks and pH sensitivity issues, making accurate quantification challenging for cardiovascular disease risk assessment.
Innovation Solution
The method involves identifying a defined TMAO peak region between 3.2 and 3.4 ppm in a proton NMR spectrum by using a pH-stable reference peak and a pH-variable calibration peak, with curve fitting functions to account for misalignments, allowing for precise measurement of TMAO levels in biosamples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional peak identification methods are used in NMR spectra, then the analysis process is simple, but measurement precision deteriorates due to overlapping peaks and pH sensitivity
Solution Approach 1:
The patent applies preliminary action by performing curve fitting to predict the TMAO peak location before actual measurement. The system uses a predicted peak location based on pH-dependent calibration to guide the measurement process, ensuring that the integration window is correctly positioned even before the actual NMR spectrum is fully analyzed. This preliminary prediction resolves the contradiction by establishing an accurate measurement framework in advance that accounts for pH variations and peak overlaps.
Solution Approach 2:
The patent implements feedback through an iterative process where the measured NMR spectrum is compared against the predicted peak location, and the integration window is adjusted based on the actual spectrum analysis. The system uses the relationship between pH and peak position to dynamically adjust the measurement parameters, creating a closed-loop system that continuously refines the TMAO quantification accuracy while maintaining a manageable process complexity.
2Measurement precision
If pH-variable calibration peaks are used to account for pH changes, then measurement precision improves, but device complexity increases due to additional calibration requirements
Solution Approach 1:
The patent applies parameter changes by utilizing the pH-dependent relationship between the calibration peak position and the TMAO peak position. Instead of treating pH as a variable to be controlled, the invention embraces it by using pH-induced peak shifts as the basis for determining TMAO concentration. The system establishes a mathematical relationship between the calibration peak displacement and the corresponding TMAO peak location, allowing accurate measurement across different pH conditions without requiring complex pH control mechanisms.
3Measurement precision
If curve fitting functions are applied to account for misalignments, then measurement precision improves, but loss of time increases due to additional computational steps
Solution Approach 1:
The patent reduces computational time by performing preliminary curve fitting to establish the relationship between calibration peaks and TMAO peak location before actual sample analysis. The predicted peak location is calculated in advance using the pH-dependent calibration data, so that during actual measurement, the system only needs to integrate the signal within a pre-determined window rather than performing complex real-time curve fitting on every spectrum.
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 accurate and linear measurement of TMAO levels across a biological range of 1-50 μM in plasma and 0-1000 μM in urine, effectively assessing the risk of atherosclerotic cardiovascular disease by distinguishing TMAO peaks from overlapping signals.
Implementation Method 1
electronically determining a level of trimethylamine-N-oxide ('TMAO') of an in vitro biosample using a defined TMAO peak region having a single TMAO peak residing between about 3.2 and 3.4 ppm of a proton NMR spectrum
Data Source
AI summary
A defined peak region residing between about 3.2 and 3.4 ppm of a proton NMR spectrum of an in vitro biosample is electronically evaluated to determine a level of trimethylamine-N-oxide (“TMAO”). The biosample may be any suitable biosamples including human serum with a normal biologic range of between about 1-50 μM or urine with a normal biologic range of between about 0-1000 μM.