2D LC-MS/MS Assay Workflow for Low-Level Protein Detection
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Solution Overview
Problem
Existing methods for detecting large molecule analytes, such as proteins, in biological samples suffer from low sensitivity and require labor-intensive, low-throughput processes, especially when high-quality reagents are unavailable or rapid assay development is needed.
Innovation Solution
A two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) system with high and low pH RPLC stages, combined with affinity capture, allows for automated detection and enhanced sensitivity by collecting specific eluate portions in a trap column, followed by MS analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional LC-MS/MS is used without enrichment, then the assay is reagent-independent and easier to perform, but the sensitivity is relatively low (100 ng/mL to low μg/mL range)
Solution Approach 1:
The invention segments the analysis into two distinct LC dimensions: first dimension at high pH for initial separation and enrichment, second dimension at low pH for final separation and MS analysis. This segmentation allows each dimension to be optimized for its specific function, achieving both ease of operation and high sensitivity.
Solution Approach 2:
The invention transitions from one-dimensional LC-MS/MS to two-dimensional LC-MS/MS by adding a first dimension of high pH RPLC before the conventional low pH RPLC. This dimensional expansion provides additional separation power and enrichment capability, improving sensitivity while maintaining reagent independence.
2Measurement precision
If 2D-LC approaches are used to enhance sensitivity, then detection sensitivity improves (pg/mL to low ng/mL range), but the process becomes labor intensive and low throughput
Solution Approach 1:
The invention merges two LC systems into a single integrated platform that performs both high pH and low pH RPLC sequentially. This consolidation eliminates the need for manual sample transfer between separate systems, automates the 2D-LC process, and significantly improves throughput while maintaining the sensitivity benefits of 2D separation.
Solution Approach 2:
The single LC system is designed to perform multiple functions: it can operate in high pH mode for the first dimension separation, then switch to low pH mode for the second dimension separation and MS analysis. This multi-functionality allows one system to replace what previously required multiple separate systems and manual operations.
3Manufacturing precision
If high-pH RPLC fractionation is used, then peptide separation resolution and recovery improve, but the process requires offline processing and is labor intensive
Solution Approach 1:
The invention combines high-pH RPLC fractionation with low-pH RPLC analysis in a single online system. The high-pH separation occurs first, then the separated peptides are directly transferred to the low-pH column for further separation and MS analysis without manual intervention. This online integration maintains high resolution while eliminating labor-intensive offline processing.
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
The method achieves at least 30-fold greater sensitivity than single dimension HPLC-tandem MS, enabling detection of analytes at concentrations as low as 10 fmol/μg total protein in tissues and 10 pg/mL in fluids, and is fully automated.
Implementation Method 1
reversed phase liquid chromatography (RPLC)
Implementation Method 2
mass spectrometry (MS)
Implementation Method 3
affinity capture
Data Source
AI summary
The present application relates to systems and methods for assaying presence of large molecule analytes, such as proteins, e.g., antibodies, antigens, receptors, and the like, using a targeted two-dimensional liquid chromatography, tandem mass spectrometry (2D-LC-MS/MS) system, optionally combined with affinity capture. In some aspects, the system is partially or fully automated. In some aspects, the system may allow detection of protein biomarkers (e.g., antibodies or antigens) from clinical or nonclinical biological tissue or fluid samples in the pg/mL to ng/mL range.