Pipetting Arm Dead Volume Reduction via Bottom Detection
Solution Overview
Problem
Automated liquid handling systems face challenges in minimizing dead volume, leading to waste of expensive and rare chemicals due to a compromise between safety and resource exploitation, as they often rely on predetermined safety limits that result in unnecessary liquid wastage.
Innovation Solution
A method and system that determine the actual available liquid volume by moving the pipetting arm to the actual bottom of the vial and calculating the safety-corrected stop position, allowing for precise liquid handling and reducing dead volume through hysteresis correction, enabling better exploitation of the liquid without compromising safety or accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined safety limit is defined to prevent aspiration of air and ensure safe liquid handling, then safety and accuracy of liquid handling is improved, but dead volume increases and expensive chemicals are wasted
Solution Approach 1:
The system performs a preliminary determination of the actual liquid volume in the vial by moving the pipetting arm to the actual bottom of the vial and detecting the liquid level. This preliminary measurement allows the system to calculate the true available liquid volume before executing aspiration steps, enabling optimized liquid handling that avoids both waste and safety issues.
Solution Approach 2:
The system continuously monitors the liquid level in the vial during the aspiration process and uses this feedback information to adjust the pipetting operations. By detecting the actual liquid level and comparing it with the predetermined safety limit, the system can dynamically control the aspiration volume to maximize chemical utilization while maintaining safety.
2Reliability
If a predetermined safety limit is defined to prevent aspiration of air, then reliability is improved, but productivity decreases due to unnecessary liquid wastage
Solution Approach 1:
The system performs a preliminary determination of the actual liquid volume in the vial by moving the pipetting arm to the actual bottom of the vial and detecting the liquid level. This preliminary measurement allows the system to calculate the true available liquid volume before executing aspiration steps, enabling optimized liquid handling that avoids both waste and safety issues.
Solution Approach 2:
The system changes the parameter of liquid volume determination from a fixed predetermined safety limit to a dynamically calculated actual liquid volume based on real-time detection. This parameter change enables the system to adapt the aspiration volume to the actual liquid available, maximizing chemical utilization while maintaining safety through continuous monitoring.
3Loss of substance
If the pipetting arm moves to the actual bottom of the vial to determine liquid volume, then dead volume is reduced, but device complexity increases
Solution Approach 1:
The pipetting arm is designed to perform multiple functions: it not only executes aspiration operations but also determines the actual liquid volume by moving to the bottom of the vial and detecting the liquid level. This multi-functionality reduces the need for separate measurement devices and minimizes overall system complexity while achieving dead volume reduction.
Data Source
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Figure 2
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AI summary
A method for minimizing the dead volume (Vd) in a vial (10) presenting a liquid (L) for aspiration is provided. The method comprises, after determining that the liquid volume (Vi) indicated to be available in the vial (10) is not sufficient for a further aspiration step, moving downward in direction towards the bottom of the vial (10) by means of a pipetting arm (20) presenting a pipetting tip (21) and along the z-axis of the pipetting arm (20) until the pipetting arm (20) comes to a stop in a first stop position (Slz). Then, the actual available liquid volume (Va) is calculated based i.a. on said first stop position (Slz). In case the calculated actual available liquid volume (Va) is sufficient, a further aspiration step can be executed. Furthermore, a liquid handling system for minimizing dead volume (Vd), a computer-implemented method for controlling a pipetting arm (20) of such a liquid handling system, and the use of a hysteresis determination method for minimizing dead volume (Vd) are provided.