Seamless Sampling Needle with Equal Inner Diameters to Eliminate Carry-Over
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Solution Overview
Problem
The increased sensitivity of liquid chromatography apparatuses leads to carry-over issues, where residual samples from previous measurements contaminate subsequent analyses, degrading reliability, and existing cleaning methods fail to completely prevent this contamination.
Innovation Solution
A seamless sampling needle with a sampling part and a sample holding part of equal inner diameters, arranged as a single, integrally formed tube, and a sample injection apparatus that uses this needle to ensure smooth sample flow and prevent residual sample retention, featuring a flexible part with a smaller external diameter for deformation and attachment to external mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensitivity of the liquid chromatography apparatus is increased, then the detection capability is improved, but carry-over occurs causing false detection of residual samples
Solution Approach 1:
The sampling needle is divided into two distinct parts: a sampling part with a first inner diameter and a sample holding part with a second inner diameter. This segmentation allows the sample to be held in a restricted space with a smaller cross-sectional area, preventing residual sample from remaining in the sampling needle after injection, thereby eliminating carry-over while maintaining high detection sensitivity.
2Object-generated harmful factors
If cleaning processes are applied to the sampling needle and injection port, then sample removal is attempted, but carry-over peaks still occur indicating incomplete cleaning
Solution Approach 1:
The invention extracts the sample holding function from the sampling needle by providing a separate sample holding part with a distinct inner diameter. This design extracts the residual sample from the sampling needle itself and confines it to the sample holding part, which has a smaller cross-sectional area that prevents sample adhesion and ensures complete sample discharge, thereby preventing carry-over without requiring extensive cleaning processes.
3Ease of operation
If a seamless structure with equal inner diameters is used for sampling and sample holding parts, then sample flow smoothness is improved, but sample retention is prevented
Solution Approach 1:
The invention applies local quality by giving different inner diameters to different parts of the sampling needle. The sampling part has a first inner diameter optimized for sample intake, while the sample holding part has a second inner diameter that is smaller to prevent sample retention. This local variation in dimensional quality ensures smooth sample flow during extraction while preventing sample adhesion and retention in the holding part, thereby eliminating carry-over.
Data Source
AI summary
A sampling needle is disclosed that includes a sampling part that is inserted into a sample, and a sample holding part that holds the sample that is introduced through the sampling part. The sampling part and the sample holding part are arranged into a seamless structure, and the inner diameter of the sampling part and the inner diameter of the sample holding part are equal.