Hydrogen Sulfide Quantification Using 34S Isotope Dilution
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Solution Overview
Problem
Current methods for quantifying hydrogen sulfide (H2S) are limited by difficulties in measuring volatile molecules, interference from contaminants, the need for specialized equipment, and lack of an internal standard, particularly affecting the practicality and accuracy of in vitro clinical diagnostics.
Innovation Solution
The use of 34S isotope-labeled sodium sulfide as a standard in isotope dilution mass spectrometry, combined with a reducing agent like tris(2-carboxyethyl) phosphine (TCEP) and a derivatizing agent like ethyl iodoacetate, allows for the precise quantification of H2S and thiols in biological samples through liquid chromatography and tandem mass spectrometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lead acetate color change method is used to quantify H2S, then the measurement process is simple, but it cannot quantify in vivo H2S levels at the time of sample collection and only measures subsequent synthetic enzyme capacity
Solution Approach 1:
The patent uses an internal standard (isotope-labeled H2S or thiol compound) as an intermediary substance that co-extracts with the target analyte. This internal standard serves as a reference to correct for losses during sample preparation and variations in extraction efficiency, enabling accurate quantification of in vivo H2S levels while maintaining a relatively simple measurement process
Solution Approach 2:
The patent changes the measurement parameter from indirect enzyme capacity assessment to direct H2S concentration measurement by using mass spectrometry detection with isotope dilution. This allows quantification of actual H2S levels present at the time of sampling rather than measuring subsequent synthetic capacity
2Measurement precision
If monobromobimane derivatization is used for H2S quantification, then fluorescence detection is achieved, but the reagent has poor ionization characteristics and is light sensitive requiring storage and reactions in the dark
Solution Approach 1:
The patent replaces the light-sensitive monobromobimane reagent with derivatization reagents that are stable to light and do not require special storage conditions. These alternative reagents achieve sufficient derivatization for mass spectrometry detection without the fragility and handling complexity of fluorescent probes
Solution Approach 2:
The patent substitutes fluorescence detection with mass spectrometry detection. This replacement eliminates the need for light-sensitive reagents and dark storage conditions, as mass spectrometry detects ions directly without requiring optical properties of the derivatization reagent
3Adaptability or versatility
If external calibration curves are used for H2S detection, then the method is widely applicable, but accuracy is compromised due to lack of internal standard
Solution Approach 1:
The patent introduces an internal standard (isotope-labeled H2S or structurally similar thiol compound) as an intermediary reference substance that undergoes the same extraction and derivatization process as the target analyte. By comparing the ratio of analyte signal to internal standard signal, the method corrects for variations in extraction efficiency and instrument response, maintaining both versatility and accuracy across different samples and laboratories
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 provides accurate, high-throughput quantification of H2S and thiols with minimal interference, enabling reliable clinical diagnostics and risk prediction for diseases such as cardiovascular disorders.
Implementation Method 1
isotope dilution mass spectrometry
Implementation Method 2
analyzing the derivatized sample by isotope dilution mass spectrometry
Implementation Method 3
the reducing agent is an agent capable of reducing polysulfides
Implementation Method 4
incubating the sample with a derivatizing agent to form a derivatized sample
Data Source
AI summary
The present invention relates to methods, compositions, systems, and kits for the analysis of hydrogen sulfide using an 34S isotope-labeled sulfide compound (e.g., 34S isotope-labeled sodium sulfide), a reducing agent and derivatization reagent, in particular by isotope dilution mass spectrometry.