Cortisol Detection in Sweat via HPLC-MS
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Solution Overview
Problem
Current cortisol analysis methods, particularly immunoassays, face specificity issues due to antibody cross-reactions with other steroids and drugs, leading to false positives, and invasive blood sampling methods can alter stress levels, making non-invasive and accurate cortisol detection in biofluids like sweat challenging.
Innovation Solution
A sensitive HPLC-tandem mass spectrometry method using liquid-liquid extraction and atmospheric pressure chemical ionization (APCI) with selected reaction monitoring (SRM) is developed for quantifying cortisol and metabolites in eccrine sweat, allowing for the separation of cortisol from interfering isomers and achieving precise detection in human eccrine sweat samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If immunoassay methods are used for cortisol analysis, then the detection process is simple and widely adopted, but specificity problems occur due to antibody cross-reaction with other steroids and drugs leading to false positive results
Solution Approach 1:
The patent replaces immunoassay methods with HPLC-tandem mass spectrometry, substituting a biochemical detection system with a physical-chemical separation and detection system. This substitution eliminates antibody cross-reaction issues while maintaining detection capability, directly resolving the contradiction between ease of detection and specificity.
Solution Approach 2:
The patent changes the detection parameters from antibody-based recognition to mass-to-charge ratio measurement. By measuring the precise mass of cortisol molecules and their fragment ions, the method achieves high specificity without relying on antibodies that cross-react with other steroids and drugs.
2Measurement precision
If blood sampling is used for cortisol detection, then accurate measurement is achieved, but the invasive procedure alters stress levels and introduces artifacts and erroneous results
Solution Approach 1:
The patent uses sweat as an intermediary matrix to indirectly measure cortisol levels. Instead of directly sampling blood, the method detects cortisol that has been secreted into sweat, providing a non-invasive proxy measurement that preserves the subject's natural stress state while still enabling accurate cortisol quantification.
Solution Approach 2:
The patent inverts the traditional approach by measuring cortisol in sweat rather than in blood. This inversion transforms an invasive measurement problem into a non-invasive solution, allowing accurate cortisol detection without the harmful stress-altering effects of blood sampling.
3Ease of operation
If non-invasive methods like urine and saliva collection are used, then invasive procedures are avoided, but reliability problems occur as these biofluids are not ideal sources for cortisol detection
Solution Approach 1:
The patent changes the detection parameters specifically for sweat analysis, optimizing liquid-liquid extraction conditions and mass spectrometry detection parameters to achieve reliable cortisol measurement in this novel matrix. This specialized parameter optimization enables sweat to become a reliable source, surpassing the reliability of urine and saliva while maintaining non-invasive collection advantages.
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 method enables non-invasive, sensitive, and specific detection of cortisol and metabolites in eccrine sweat with low limits of detection and quantitation, providing a reliable means to assess stress levels without the artifacts associated with invasive blood sampling.
Implementation Method 1
HPLC-tandem mass spectrometry method
Implementation Method 2
atmospheric pressure chemical ionization (APCI) with selected reaction monitoring (SRM)
Implementation Method 3
atmospheric pressure chemical ionization (APCI)
Implementation Method 4
liquid-liquid extraction using ethyl acetate
Data Source
AI summary
Provided herein are kits, compositions and methods for biomarker detection, and the use of relative or absolute levels of these markers for non-invasive detection of stress and/or relaxation levels in human subjects. In particular, the present invention relates to cortisol, isomer and metabolite markers for stress and/or relaxation levels.