Low-Field NMR Spectrometer Analyte-Specific Pulse Sequences
Solution Overview
Problem
Low-field NMR spectrometers are not suitable for analyzing complex liquid mixtures, such as biofluids, due to signal overlap, making it difficult to reliably quantify metabolites like triglycerides and cholesterol, which is essential for disease prediction and diagnosis, but high-resolution NMR and mass spectrometers are expensive and not available for on-site applications.
Innovation Solution
A method using analyte-specific high-frequency pulses in low-field NMR spectrometers to selectively excite specific analytes, allowing for clear detection and quantification by iteratively determining and applying high-frequency pulses optimized using algorithms like the Krotov method, enabling the analysis of metabolites in biofluids with low-cost, portable equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution NMR spectrometers with magnetic field strength exceeding 20 T are used, then measurement precision and spectral dispersion are improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent changes the operating parameters of the NMR spectrometer by using a low magnetic field strength (up to 3 T) instead of high field strengths (20 T+). This parameter change is compensated by implementing a specific pulse sequence method that creates spectral dispersion through time-domain encoding rather than relying on high-field frequency separation, thus achieving metabolite resolution without expensive high-field magnets
Solution Approach 2:
The patent replaces the traditional spatial-frequency-based detection mechanism (relying on high magnetic field for frequency separation) with a time-domain encoding mechanism. By using specific pulse sequences that encode metabolite information in temporal patterns rather than frequency positions, the system substitutes the mechanical/physical requirement for high-field magnets with a signal processing approach
2Ease of manufacture
If low-field NMR spectrometers with magnetic field strength up to 3 T are used, then device cost and portability are improved, but measurement precision deteriorates due to insufficient spectral dispersion
Solution Approach 1:
The patent transforms the low-field limitation into an advantage by changing the detection parameter from frequency-domain to time-domain. The pulse sequence method encodes metabolite signals in temporal patterns that can be decoded even with limited frequency separation, effectively converting the low-field constraint into a workable measurement approach
Solution Approach 2:
The patent applies local quality by targeting specific metabolite signals with selective pulse sequences. Instead of attempting to resolve all signals simultaneously across the spectrum, the method focuses on exciting and detecting specific metabolite resonances with tailored pulse parameters, achieving precise measurement of individual metabolites despite overall spectral crowding
3Ease of operation
If conventional radiofrequency pulses are used in low-field NMR, then ease of operation is maintained, but measurement precision deteriorates due to signal overlap of multiple metabolites
Solution Approach 1:
The patent segments the complex task of metabolite analysis by using a library of metabolite-specific pulse sequences. Each pulse sequence is designed to selectively excite and detect a specific metabolite, dividing the overall analysis into discrete, manageable components that can be applied sequentially or selectively based on the analytical needs
Solution Approach 2:
The patent introduces an intermediary layer of signal processing between the simple radiofrequency pulse application and the final metabolite detection. The pulse sequence acts as an intermediary that transforms the simple pulse input into metabolite-specific signal patterns, enabling discrimination of overlapping metabolite signals through temporal encoding rather than frequency separation
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 and cost-effective analysis of metabolites in biofluids using low-field NMR spectrometers, allowing for on-site applications in medical practices and security checkpoints, overcoming the limitations of signal overlap and equipment costs.
Implementation Method 1
High-resolution nuclear magnetic resonance (NMR) spectroscopy is fundamentally suitable for this purpose
Data Source
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AI summary
A method for detecting and quantifying individual analytes in liquid analyte mixtures by means of NMR spectroscopy, in which a radiofrequency pulse is applied to a sample of the analyte mixture in an NMR spectrometer and the resultant NMR spectrum is evaluated, is intended to be developed further in such a way that it facilitates an exact analysis of liquid analyte mixtures, even in the case of using the low-field NMR spectrometers. To this end, the sample of the analyte mixture is arranged in a low-field NMR spectrometer and at least one radiofrequency pulse that only excites a specific analyte is applied thereto.