Peptide Metal Complexes for DMS Separation
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Solution Overview
Problem
Current methods for mass spectrometric detection and quantitation of peptides, especially cyclic peptides like oxytocin, face challenges due to inefficient fragmentation and sensitivity losses, and existing differential mobility spectrometry techniques struggle with discrimination between charged species and proton stripping, leading to suboptimal detection and quantitation, especially in complex biological samples.
Innovation Solution
Forming peptide metal complexes with calcium salts and transporting them through a differential mobility spectrometer, with the addition of chemical modifiers like DMSO, to enhance separation and prevent proton stripping, allowing for accurate quantification and improved discrimination between charged species.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mass spectrometric detection is used for peptide quantitation, then unique MRM transitions can be selected, but sensitivity losses occur due to inefficient fragmentation especially for cyclic peptides
Solution Approach 1:
The patent changes the ionization state parameter by forming multiply charged peptide ions through metal complexation instead of relying on traditional singly charged ion fragmentation. This allows cyclic peptides to be detected without efficient fragmentation, eliminating sensitivity losses while maintaining quantitation accuracy through charge state discrimination in the DMS.
Solution Approach 2:
The patent replaces the mechanical fragmentation process in traditional MS/MS with a field-based separation mechanism in the differential mobility spectrometer. Instead of physically breaking down peptides to detect fragments, the system uses electric fields to separate intact multiply charged peptide ions from chemical noise based on their mobility differences.
2Manufacturing precision
If differential mobility spectrometry is used to separate peptides, then separation based on charge states is achieved, but proton stripping occurs leading to hindered detection of multiply charged ions
Solution Approach 1:
The patent applies preliminary action by forming stable metal-peptide complexes before introducing the sample to the DMS. This pre-complexation stabilizes the multiply charged ions and prevents proton stripping during the mobility separation process, ensuring reliable detection while maintaining separation resolution.
3Measurement precision
If sample preparation techniques such as immunocapture or nanoLC are used, then peptide detection in crude samples is improved, but cost and complexity increase due to column loading care and optimization requirements
Solution Approach 1:
The patent extracts the peptide separation function from complex sample preparation procedures and transfers it to the differential mobility spectrometer. By using DMS to separate peptides from chemical noise based on mobility differences, the method eliminates the need for complex immunocapture or nanoLC steps, reducing both cost and operational complexity while maintaining detection accuracy in crude samples.
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 effective separation and quantitation of peptides, reducing proton stripping and enhancing discrimination between charged species, thereby improving the accuracy and sensitivity of peptide detection in complex samples.
Implementation Method 1
transporting said mixture through a differential mobility spectrometer to effect separation of said one or more peptide calcium ion complexes
Implementation Method 2
combining the sample comprising one or more peptides with a solution comprising a calcium salt, so as to form one or more peptide calcium complexes
Implementation Method 3
ionizing said one or more peptide calcium complexes so as to form one or more peptide calcium ion complexes
Implementation Method 4
addition of chemical modifiers like DMSO, to enhance separation and prevent proton stripping
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Methods and systems for separating and/or quantifying peptides using differential mobility spectrometry (DMS) are provided herein. In accordance with various aspects of the applicant's teachings, the methods and systems can provide for the separation of one or more peptides, for example, peptides that may be difficult to separate with conventional techniques, such as mass spectrometry (MS), by complexing the peptides with a metal cation (e.g., Ca2+) prior to DMS. In some aspects, the present teachings can prevent proton stripping from ionized peptides that can occur in DMS to prevent unintended and/or undesirable alterations to the peptide's charge state distribution.