Off-column vertical chemiluminescence detection device for capillary electrochromatography

Abstract

The invention provides an off-column vertical chemiluminescence detection device for capillary electrochromatography. The detection device comprises a cell body, a spectrum detection window, a photomultiplier and the like. The detection device is characterized in that the capillary electrochromatography column and a chemiluminescence detection passage are arranged in a vertical position; the easily corroded part of the capillary electrochromatography column, which is exposed in a strongly alkali chemiluminescence reagent is extremely small; after leaving the column, the substance to be measured separated by the chromatographic column and the chemiluminescence reagent can quickly react and generate photoelectric response signals. The detection device has simple manufacture process, convenient usage and low cost, can effectively reduce the corrosion degree of the capillary electrochromatography, can eliminate the phenomenon that the alkali solution corrodes the chromatographic column packing material, and can prolong the service life of the separation column; the optical signals generated by the detection cell can be collected duly, the signal loss is small, the sensitivity is high,the stability and the repeatability are excellent, and the detection device can realize quick separation and high-sensitivity detection on the substances with chemiluminescence activity.

Description

technical field [0001] The invention relates to the design of an off-column vertical chemiluminescence detection device for capillary electrochromatography. Background technique [0002] Capillary electrochromatography (CEC)-chemiluminescence (CL) combined technology combines the characteristics of high selectivity of CEC and high sensitivity of CL, and is currently an efficient and rapid separation and analysis method in microanalysis. (Lin, Z., Xie, Z., Lü, H., Lin, X., Wu, X., Chen, G., Anal. Chem., 2006, 78, 5322-5328.) CEC-CL combination The technical key lies in the detection interface connecting the two, and the performance of the interface directly affects the separation efficiency and detection sensitivity of the capillary column. [0003] The existing CEC-CL interfaces mainly include: on-column coaxial flow detection interface and off-column coaxial flow detection interface (Lin, Z., Xie, Z., Lü, H., Lin, X., Wu, X., Chen, G., Anal. Chem., 2006, 78, 5322-5328; Li...

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Problems solved by technology

Among them, in the column coaxial flow type, the detector is located between the high-voltage power supply, and the post-column reaction reagents such as H 2 o 2 In alkaline medium, it is easy to decompose and generate bubbles, resulting in unstable current, and driven by the electric field, the alkaline reagent will reversely migrate into the capillary column and react with the silica gel-based modified filler in the column, resulting in column damage

In the off-column coaxial flow method, the ground electrode is moved from the end of the reaction capillary column to the front of the capillary column, which avoids the decomposition of reagents behind the column to generate bubbles under the electric field, but the reagents are still under the action of the electric field and may migrate into the separation capillary front end, causing column packing to collapse

It is worthy of attention that the coaxial flow interface generally adopts the sleeve type, which has a big disadvantage: when the analyte flows out of the separation column into the reaction tube with a large inner diameter and mixes with the luminescent reagent, it is easy to cause vortex diffusion, resulting in peak Broadening reduces column efficiency and detection sensitivity; at the same time, using a coaxial flow interface, the capillary electrochromatographic column is soaked in a strong alkaline luminescent system for a long time, and the capillary electrochromatographic column cannot withstand strong alkalinity (generally tolerate pH<10), Long-term immersion will cause the chromatographic column to be brittle and broken, and under the action of the electric field, the alkali solution may migrate into the separation capillary column, corrode the packing in the column and cause it to collapse and leak, resulting in reduced column efficiency, reproducibility and service life. Moreover, the leakage of the filler will block the subsequent reaction capillary and waste liquid pipe, which will affect the detection and analysis of chemiluminescence.

[0004] At present, a method with a clear structure has not been proposed, which can reduce the influence of eddy current diffusion when the capillary electrochromatography coaxial flow interface solution is mixed, or prevent the capillary electrochromatography separation column from soaking in alkali solution for a long time, and prevent the luminescent reagent from migrating into the capillary due to the action of the electric field. Design of Chemiluminescence Detection Device for Electrochromatographic Column

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