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Method for activating tenax sampling tubes

A sampling tube and back-purging technology, applied in the field of environmental gas pollutant analysis, can solve the problems of high cost, can not meet the needs of daily detection work, low efficiency, etc., and achieve the effect of reducing processing cost, easy operation and simple operation

Active Publication Date: 2018-05-04
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The main purpose of the present invention is to provide a method for activating the tenax sampling tube, so as to solve the problems in the prior art that the cost is high, the efficiency is low, and the needs of daily detection work cannot be met.

Method used

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  • Method for activating tenax sampling tubes
  • Method for activating tenax sampling tubes
  • Method for activating tenax sampling tubes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Using the back-purging-desorption function on the thermal desorption instrument, inject 1.0 μL of methanol (chromatographically pure) into the tenax sampling tube, and use nitrogen with a flow rate of 80ml / min as the carrier gas to back-purge the tenax sampling tube at room temperature for 5 minutes ;

[0036] Then place it at a high temperature of 250°C for desorption for 5 minutes;

[0037] Finally, at a high temperature of 250°C, nitrogen gas with a flow rate of 100ml / min was used as the carrier gas and then back-purged for 10 minutes to obtain an activated tenax sampling tube. The entire sampling tube activation process is 20min.

Embodiment 2

[0039] Using the back-purging-desorption function on the thermal desorption instrument, inject 1.5 μL of methanol (chromatographically pure) into the tenax sampling tube, and use helium with a flow rate of 50ml / min as the carrier gas to back-purge the tenax sampling tube at room temperature 2min;

[0040] Then place it at a high temperature of 325°C for desorption for 8 minutes;

[0041] Finally, at a high temperature of 325°C, nitrogen with a flow rate of 150ml / min was used as the carrier gas and then back-purged for 5 minutes to obtain an activated tenax sampling tube. The entire sampling tube activation process is 15min.

Embodiment 3

[0043] Using the back-purging-desorption function on the thermal desorption instrument, inject 1.5 μL of methanol (chromatographically pure) into the tenax sampling tube, and use nitrogen with a flow rate of 100ml / min as the carrier gas to back-purge the tenax sampling tube for 4 minutes at room temperature ;

[0044] Then place it at a high temperature of 250°C for desorption for 10 minutes;

[0045] Finally, at a high temperature of 250°C, nitrogen with a flow rate of 150ml / min was used as the carrier gas and then back-purged for 10 minutes to obtain an activated tenax sampling tube. The entire sampling tube activation process is 24min.

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Abstract

A method of activating a tenax sampling tube is provided. The method includes adding methanol into the tenax sampling tube, subjecting the tenax sampling tube to a first time of back flushing by utilizing a carrier gas, desorbing the tenax sampling tube after the first time of back flushing at 250-325 DEG C, putting the desorbed tenax sampling tube at 250-325 DEG C, and performing a second time of back flushing by utilizing the carrier gas to obtain an activated tenax sampling tube. Through injection of the methanol that is an extractant and through back flushing of the sampling tube by utilizing the carrier gas, the extractant is in full contact with a solid adsorbent and effectively extracts residues and impurities in the adsorbent; and then after high-temperature desorption at 250-325 DEG C, the remainder residues and impurities are gasified themselves at a high temperature or carried by gasification of the extractant, the gasification efficiency is high, and rapid and efficient activation of the tenax sampling tube is achieved through back flushing. Operation is simple and the cost is low.

Description

technical field [0001] The invention relates to the field of environmental gas pollutant analysis, in particular to a method for activating a tenax sampling tube. Background technique [0002] Tenax sampling tubes are commonly used in the analysis of benzene and TVOC in room air or ambient air by thermal desorption capillary gas chromatography. The tenax sampling tube is a glass tube filled with tenax adsorbent or a stainless steel tube with a smooth inner wall. Before sampling, the sampling tube and adsorbent must be activated to reduce the blank of the sampling tube as much as possible. GB / T18883-2002 requires "to minimize interference"; GB50325-2010 requires that "before use, it should be heated and activated with nitrogen, the activation temperature should be higher than the thermal desorption temperature, the activation time should not be less than 30min, and the activation should be free of impurities. peak”; in Appendix E of DBJ01-91-2004, it is clearly required that...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N30/54
Inventor 刘生丽王兴华高金桥薛德山郭建江倪丰平
Owner PETROCHINA CO LTD