Low-Pressure Dual-Gradient Refocusing for Faster Chromatography
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Solution Overview
Problem
Current chromatographic systems suffer from long dwell times and low chromatographic duty cycles due to slow delivery of mobile phase gradients, particularly in nano-flow LC-MS analyses, which affect the efficiency and sensitivity of biomolecule separation.
Innovation Solution
A system is developed that performs most fluid handling steps at low pressure, with the exception of final elution through the separation column, using parallel gradient formation and elution to stagger analyses, and employs a holding loop for temporary storage of partly separated analytes before high-pressure chromatographic separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If nano-flow LC is used to achieve high analytical sensitivity, then sensitivity is improved, but cycle time increases and duty cycle decreases
Solution Approach 1:
The system divides the chromatographic process into two distinct segments: a trapping column operating at low pressure for sample loading and desalting, and an analytical column operating at high pressure for separation. This segmentation allows each column to be optimized for its specific function, enabling high sensitivity at the trapping stage while maintaining fast duty cycle at the analytical stage.
Solution Approach 2:
The trapping column acts as an intermediary between sample injection and the analytical column. It performs preliminary sample preparation (loading and desalting) at low pressure, then transfers the prepared sample to the analytical column for high-pressure separation, effectively mediating between the conflicting requirements of sensitivity and productivity.
2Measurement precision
If low flow rates are used in nano-flow LC, then sensitivity is improved, but analysis time increases
Solution Approach 1:
The system dynamically adjusts flow rates for different operational stages: low flow rates (200-400 nL/min) during trapping column operations to maximize sensitivity, and high flow rates during analytical column operations to minimize analysis time. This dynamic flow rate adjustment resolves the contradiction between sensitivity and analysis time.
3Manufacturing precision
If high pressure is applied throughout the system, then separation efficiency is improved, but system wear increases and sensitivity decreases
Solution Approach 1:
The system applies high pressure locally only at the analytical column where separation efficiency is critical, while keeping the trapping column and associated fluid handling systems at low pressure. This localized pressure application maintains resolving power while minimizing overall system wear and complexity.
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 time, increases chromatographic duty cycle, and maintains resolving power while minimizing peak broadening and system wear, allowing near 100% duty cycle operation.
Implementation Method 1
a first column (30) having a sorbent for trapping the analytes
Implementation Method 2
one, two, or more fluid pumps connected in parallel for delivering a mobile phase at a flow rate of 300 nL/min to 50 μL/min through said first column at a pressure of 100 kPa to 5000 kPa
Implementation Method 3
one, two, or more holding loops wherein the mobile phase gradient(s) and the partly separated analytes eluted from the first column may be stored
Implementation Method 4
a chromatography column, where the gradient and analytes in said loop is forced therethrough
Data Source
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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.