Adjustable Ascent Speed Sampling Needle Reduces Carryover
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Solution Overview
Problem
High-speed upward movement of the sampling needle in liquid chromatograph systems results in significant liquid sample carryover due to incomplete detachment from the needle's outer wall, leading to contamination in subsequent measurements, and existing solutions like low-wettability needles are expensive and inefficient.
Innovation Solution
A liquid-sample collecting system that allows adjustable ascent speed of the sampling needle, determined by user input or a data table correlating sample type with optimal ascent speed, to minimize carryover while maintaining efficient sample collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sampling needle is moved upward at a high speed to improve analysis efficiency, then the productivity increases, but the liquid sample remains on the outer wall of the needle causing carryover contamination
Solution Approach 1:
The system dynamically adjusts the ascent speed of the sampling needle based on the detected liquid level height. When the needle is pulled up from the liquid surface, the ascent speed is controlled to prevent excessive liquid sample attachment on the outer wall, thereby reducing carryover while maintaining efficient sample collection
Solution Approach 2:
The invention changes the ascent speed parameter according to the liquid level height. By optimizing the ascent speed to be appropriate rather than always high, the system reduces liquid sample remaining on the needle outer wall while still maintaining good analysis efficiency
2Object-generated harmful factors
If a sampling needle made of resin or noble metal with low wettability is used to decrease liquid sample attachment, then the carryover is reduced, but the device cost increases and effectiveness is insufficient for all liquid samples
Solution Approach 1:
Instead of changing the material of the sampling needle, the invention changes operational parameters (ascent speed) to control liquid sample attachment. This approach achieves reduced carryover without increasing device cost or requiring specialized materials that may not work for all liquid samples
3Object-generated harmful factors
If the ascent speed of the sampling needle is decreased to reduce liquid sample attachment on the outer wall, then the carryover is reduced, but the time required for sample collection increases
Solution Approach 1:
The system dynamically adjusts ascent speed based on liquid level height rather than using a fixed low speed. This allows the needle to move at optimized speeds that reduce carryover while minimizing the time penalty, achieving a balance between contamination reduction and efficiency
Solution Approach 2:
By optimizing the ascent speed parameter according to actual liquid level conditions, the system achieves the minimum necessary speed to prevent excessive liquid attachment while maintaining reasonable sample collection time
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
Significantly reduces carryover during sample collection, improving measurement accuracy without requiring users to manually determine optimal ascent speeds for each sample type, thus enhancing the efficiency and reducing user workload.
Implementation Method 1
the liquid sample attaches onto the outer wall of the sampling needle due to its surface tension
Implementation Method 2
the portion of the liquid sample being dragged upward from the liquid surface is pulled downward by a gravitational force
Data Source
AI summary
Provided is a liquid-sample collecting system and liquid-sample collecting method that can decrease the amount of carryover in the process of collecting a liquid sample while maintaining the efficiency of collecting the liquid sample. A liquid-sample collecting system according to the present invention includes: a sampling needle to be inserted into a sample container, for collecting a liquid sample contained in the sample container; a driver for moving the sampling needle; an input unit for allowing a user enter to information for setting the ascent speed of the sampling needle; an ascent-speed determiner for setting the ascent speed based on the entered information; and a controller for controlling the driver so as to move the sampling needle downward at a predetermined descent speed in a descent phase and upward at the aforementioned ascent speed in an ascent phase.