Low-Pressure Dual-Gradient Refocusing for Faster Chromatographic Analysis
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Solution Overview
Problem
Current chromatographic systems suffer from long dwell times and low duty cycles due to slow delivery of mobile phase gradients, particularly in nano-flow LC-MS analysis, which affects the efficiency and sensitivity of biomolecule analysis.
Innovation Solution
A system is developed that performs fluid handling steps at low pressure, with the majority of the process occurring at low pressure, and only the final elution through the separation column at high pressure, using parallel gradient formation and elution to stagger analyses, and utilizing holding loops to store partly separated analytes before high-pressure chromatographic separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mobile phase gradients are delivered slowly to maintain chromatographic resolving power, then separation quality is improved, but analysis cycle time increases and duty cycle decreases
Solution Approach 1:
The system divides the chromatographic process into two distinct stages: a first column for initial separation at lower resolution with faster flow, and a second column for final high-resolution separation. This segmentation allows each column to be optimized for its specific function, enabling faster overall cycle times while maintaining high resolving power in the final separation stage.
Solution Approach 2:
The first column performs preliminary separation of the complex mixture into broader fractions before injection into the second column. This preliminary action reduces the complexity of the sample entering the high-resolution column, allowing faster elution speeds while still achieving adequate resolution for detection.
2Measurement precision
If nano-flow conditions are used to improve analytical sensitivity, then detection sensitivity is improved, but cycle time increases due to slow gradient delivery
Solution Approach 1:
The two-column configuration allows the system to operate at nano-flow conditions through the second column for high sensitivity detection, while the first column can handle larger volumes and perform initial separation at higher flow rates, thereby reducing the overall cycle time without compromising analytical sensitivity.
Solution Approach 2:
The first column performs preliminary concentration and separation of analytes before they enter the nano-flow second column. This preliminary action ensures that the sensitive detector receives concentrated samples at optimal nano-flow rates, maximizing sensitivity while the first column operates at higher flows to reduce cycle time.
3Productivity
If high pressure is applied throughout the system to speed up gradient delivery, then cycle time is reduced, but equipment wear increases and maintenance costs rise
Solution Approach 1:
The system segments the pressure application across two columns: the first column operates at lower pressure for initial separation, and only the second column requires high pressure for the final high-resolution elution. This reduces the cumulative pressure exposure on pumps, valves, and tubing throughout the system, decreasing wear and maintenance requirements.
Solution Approach 2:
High pressure is applied locally only where necessary - specifically during the elution phase through the second high-resolution column - rather than maintaining high pressure throughout the entire system. This localized high-pressure application achieves the needed cycle time reduction while minimizing equipment wear in low-pressure zones.
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 significantly reduces analysis cycle time while maintaining chromatographic resolving power, allowing for near 100% duty cycle and improved analytical sensitivity by minimizing diffusion and turbulence, and reducing equipment wear and maintenance costs.
Implementation Method 1
a first column having a sorbent for trapping the analytes
Implementation Method 2
the mobile phase gradient(s) and the partly separated analytes eluted from the first column are delivered into one, two, or more holding loops
Data Source
AI summary
There is provided a system for separation of analytes in a solution. The system encompasses a cartridge or trapping column enclosing a sorbent for binding the analytes in the solution and a conduit establishing a fluid link to a valve having a holding-loop to achieve elution through the cartridge at low pressures. Prior to entry into the loop, the eluent is diluted or modified by a confluent flow stream. The valve is switchable to a position following the elution from the cartridge for emptying the holding loop through an outlet port at high pressures comparable to those required for chromatographic columns. The system may use parallel gradient formation/elution to stagger analyses so that essentially the only analytical phase that hinders a 100% duty cycle is the time required for moving the first analyte from the valve and to the detector.