KR20010001034A - Thermal desorption and fractional injection system - Google Patents

Abstract

PURPOSE: A device for injecting sample separated and adhered by heat in a volatile organic compound analyzer is provided to improve reliability in measurement by preventing tailing phenomenon during a sample injection. CONSTITUTION: A device for injecting sample separated and adhered by heat in a volatile organic compound analyzer includes a heat-attachable separating tube(20) for collecting and containing volatile organic compound, a heating device(27) for providing heat to the heat-attachable separating tube to separate and adhere the collected sample from the heat-attachable separating tube, a sample drier(30) for drying the sample in contact with dried gas, a storing tank(10) connected with the heat-attachable separating tube to provide gas for separating and adhering the sample into the heat-attachable separating tube and connected with the sample drier to provide gas for separating and adhering the sample into the sample drier, a sample supplier(40) for receiving and pressing the dried sample, a third opening and shutting valve(43) mounted on a fourth connecting line(32) communicating the sample drier and the sample supplier and selectively opening and shutting the fourth connecting line, a looping device(50) for receiving a fixed amount of sample, a sample carrying gas storing tank(70), and a control valve(60) communicating or blocking between the sample supplier and the looping device and between the carrying gas storing tank and the looping device.

Description

Thermal desorption and fractional injection system of volatile organic compound analyzer

The present invention relates to a sample injection device for analyzing volatile organic compounds, and more particularly, to a sample injection device for collecting and injecting volatile organic compounds discharged from the air, water or soil into the analysis device.

Currently, gas chromatography (Gas Chromatography, hereinafter abbreviated as "GC") is used to analyze volatile organic compounds. In the case of collecting a sample of volatile organic compounds to be analyzed and injecting the collected sample into the GC by a certain amount, since the sample is highly volatile, it is liquefied and concentrated using liquid nitrogen or liquid argon. An injection method and a so-called thermal desorption method in which a gas sample is collected in a solid adsorption tube without liquefied concentration and then injected into the GC while applying heat to the adsorption tube are used.

However, the liquefied concentrated sample injection method is disadvantageous because it requires an expensive liquefied concentrated equipment, and the conventional thermal desorption method is a sample for the heating time, no matter how quickly heating the collection tube in the process of heating up and removing the sample in the collection tube. The so-called tailing phenomenon, in which desorption is not constant, occurs, and as a result, the detection limit is lowered because the sample overlaps in the GC. In order to solve this problem, the conventional thermal desorption method has a disadvantage of using an expensive specific GC column.

Therefore, the present invention is designed to solve the disadvantages of the conventionally known sample injection method, to prevent the tailing phenomenon during sample injection to improve the reliability of the measurement, and at the same time thermal desorption of economical volatile organic compound analysis apparatus applicable to general GC The purpose is to provide a sample injection device.

In order to achieve the above object, the present invention provides a desorption and dry gas storage tank that stores gas for desorption and drying of a sample, and collects and accommodates volatile organic compounds discharged from the atmosphere, water source, or soil, and to the collected sample. Samples are supplied to the heat desorption separation tube for receiving a desorption gas from the desorption / dry gas storage tank while applying heat, and to the dryer body supplied from the desorption / dry gas storage tank while passing the samples heat-desorbed from the heat desorption separation tube. A sample dryer for drying the sample dryer, a sample supply device for discharging the sample dried while passing through the sample dryer, a roofing device configured to receive a predetermined amount of the sample supplied from the sample supply device, and a roofing device Transport gas storage to store and supply the sample carrier gas that is pushed out to the sample analyzer Supplying or supplying the tank and the sample passed through the sample dryer to the roofing device, or the on-off valve for supplying or supplying the sample to be dispensed from the roofing device to the sample loop and the sample passed through the on-off valve to the sample loop or In addition to the supply cutoff, it is configured to include a control valve for supplying or blocking supply gas to the roofing device.

In addition, the present invention provides a first opening and closing valve for supplying or blocking a desorption gas supplied to the thermal desorption separation pipe from the desorption, dry gas storage tank, a first variable flow rate control valve for adjusting the flow rate and speed of the desorption gas supplied; A second opening / closing valve for supplying or blocking a dry gas supplied from the removable / dry gas storage tank to the sample dryer; and a second variable flow control valve for controlling the flow rate and speed of the dry gas passing through the second opening / closing valve. It may further include.

Therefore, according to the present invention, since the sample separated from the thermal desorption separation tube is supplied to the sample analyzing apparatus by a predetermined amount, it is possible to prevent the tailing phenomenon and improve the accuracy and reliability of the analysis value. And the present invention is economical because there is no need to use expensive equipment.

1 is a block diagram showing a schematic configuration of a sample injection device according to the present invention,

2 is a view showing the operating state of the control valve of the present invention,

(a) is a schematic diagram showing the position of the control valve in a state in which the sample is supplied from the sample supply device into the roofing device and stored in a predetermined amount;

(b) cuts off the sample supplied from the sample supply device, the control valve in the state of Figure 2a to supply the carrier gas to the roofing device the sample is stored in a certain amount to push the sample stored in the roofing device toward the sample analysis device A schematic showing the location,

(c) is a schematic diagram showing the position of a control valve in a state in which only a carrier gas is supplied into the roofing device while the sample supplied from the sample supply device is blocked to push out the sample remaining in the roofing device to clean the roofing device.

※ Explanation of code for main part of drawing

10: sample desorption and dry gas storage tank 20: thermal desorption separation tube

21: first connection line 22: first variable flow control valve

23: second connection line 24: second variable flow control valve

27: heating device 28: first opening and closing valve

29: second opening and closing valve

30: sample dryer 31: third connection line

32: fourth connection line 40: sample supply device

43: third open and close valve 45: heating device

50: roofing device 60: control valve

70: carrier gas storage tank

Hereinafter, embodiments according to the present invention will be described in detail according to the accompanying drawings.

The sample injection device according to the present invention is schematically illustrated in FIG. The present invention shown in FIG. 1 includes a desorption and dry gas storage tank 10 for storing desorption and dry gas used for desorption and drying of a sample. In another aspect, the present invention includes a thermal desorption separation tube 20 for collecting a predetermined amount of volatile organic compounds sample evaporated in the air, water source or soil, the thermal desorption separation tube 20 is the desorption, dry gas storage tank 10 and It is structured to communicate with each other on one side via one connecting line (21).

When the thermal desorption separation tube 20 is heated from the outside, the sample of the volatile organic compound collected therein is evaporated and discharged to the outside through the outlet. Is connected to the sample dryer (30). Therefore, when the thermal desorption separation tube 20 is heated to a predetermined temperature by the heating device 27 from the outside, the sample is thermally desorbed and introduced into the sample dryer 30 through the second connection line 23.

Here, the temperature for heating the thermal desorption separation tube 20 varies depending on the type of sample, but is about 200 to 350 ° C.

So-called Nafion Dryer (Nafion Dryer) is commonly used as the sample dryer (30), and the sample dryer (30) communicates with the desorption and dry gas storage tank (10) through a third connection line (31). have. The dry gas introduced from the storage tank 10 is generally used helium or nitrogen gas, and supplied into the sample dryer 30 while being supplied from the storage tank 10 and discharged through the sample dryer 30 to the outside. The sample is then contacted to dry the sample.

On the other hand, the first variable flow rate control valve 22 and the second variable flow rate control valve 24 are installed on the first connection line 21 and the third connection line 31, respectively, and their respective connection lines 21, 31) it is possible to adjust the amount of fluid supplied to the thermal desorption separation tube 20 or the sample dryer (30). This is to adjust the amount of thermal desorption separation according to the type of sample and the amount of supply of the dry matter according to the type of sample, and to control the speed of each gas.

In addition, the outlet of the sample dryer 30 is connected to the inlet side of the sample supply device 40 through the fourth connection line 32, the third opening and closing valve 43 is connected to the fourth connection line (32) It is installed. The third opening / closing valve 43 is opened when the sample is injected into the sample supply device 40 from the sample dryer 30, and on the contrary, the sample supply device 40 can supply the sample to the roofing device 50 described later. At this time, the fourth connection line 32 is blocked so that the sample discharged from the sample supply device 40 does not flow back toward the sample dryer 30, and at the same time, the sample dryer 30 flows from the sample dryer 30 toward the sample supply device 40. To prevent this from happening. And a heating device 45 is provided adjacent to the sample supply device 40, the heating device 45 is a sample contained in the sample supply device 40 by applying heat to the sample supply device 40 Is activated to make the density uniform. As this heating device 45, a heater blower is used.

In addition, the outlet of the sample supply device 40 is connected to the roofing device 50 through the control valve 60. Since the roofing device 50 is composed of a spiral loop tube, the flow rate of the sample in the loop tube is smaller than that of the straight tube, so that the sample is accommodated in the tube without being discharged unless it is pressurized from the rear. will be.

At the same time, the control valve 60 selectively connects the carrier gas storage tank 70 and the roofing device 50 with each other. Therefore, when the carrier gas is supplied from the carrier gas storage tank 70 toward the roofing device 50, the carrier gas pushes a certain amount of sample contained in the roofing device 50 toward the sample analyzer. The carrier gas is mainly used an inert gas such as helium so as not to react with the sample.

And the control valve 60 is preferably used, as shown in Figures 2a to 2c, 6-way rotary valve. In this case, a predetermined amount is supplied from the sample supply device 40 to the roofing device 50, and an operation process of distributing a predetermined amount of the sample contained in the roofing device 50 by the carrier gas and distributing it to the sample analysis device is as follows. .

Hereinafter, the operation of the present invention configured as described above will be described in detail step by step.

Sample collection step;

After separating the thermal desorption separation tube 20 from the apparatus of the present invention, the volatile organic compounds to be analyzed are installed in a river or on the ground or in the air, and when a certain amount of air is passed for a predetermined time, Volatile organic compounds or volatile organic compounds in the air discharged from the stream are introduced into the thermal desorption separation tube 20 and collected. Thus, the thermal desorption separation tube 20 which collected the sample is installed in the apparatus of this invention.

Thermal desorption separation step;

As described above, the thermal desorption separation tube 20 in which the sample is collected in the apparatus of the present invention is heated by the heating device 27. At this time, the temperature for heating the thermal desorption separation tube 20 is slightly different depending on the type of the sample is about 200 ~ 350 ℃. When the thermal desorption separation tube 20 is heated as described above, the sample collected therein is desorbed while being evaporated and introduced into the sample dryer 30 through the second connection line 23.

In the thermal desorption separation process, the first opening / closing valve 28 installed in the first connection line 21 is opened and at the same time, the first variable flow control valve 22 is adjusted so that the desorption gas is introduced into the thermal desorption separation pipe 20. By supplying the thermal desorption process is made smoothly. In this case, the flow rate of the desorption gas passing through the first variable flow rate control valve 22 is preferably set to about 5 ml / min.

Sample drying step;

When the second open / close valve 29 installed in the third connection line 31 and the second variable flow control valve 24 are adjusted, the sample dry gas stored in the removable / dry gas storage tank 10 is The sample is introduced into the sample dryer 30 through the third connection line 31 to dry the sample while contacting the sample inside the sample dryer 30. At this time, the flow rate of the dry gas passing through the second variable flow rate control valve 24 is preferably 100 ml / min.

Sample feeding and dispensing step;

The sample dried while passing through the sample dryer 30 flows toward the third opening / closing valve 43 along the fourth connection line 32 and the sample supply device 40 when the third opening / closing valve 43 is opened. Flows into). After a certain period of time in such a state, the third opening / closing valve 43 is blocked to block the sample flowing into the sample supply device 40, and then the heating device disposed adjacent to the sample supply device 40 ( By blowing hot air into the sample supply device 45 with 45), the sample contained in the sample supply device 40 is heated to activate the sample, and at the same time, to make the distribution density uniform.

Then, the third opening / closing valve 43 is closed to block the sample flowing into the sample supply device 40, and the control valve 60 is switched to the position shown in FIG. 2A. Then, when the sample supply device 40 is operated to discharge the sample contained in the sample supply device 40, the sample flows into the roofing device 50 via the control valve 60 in the direction of the solid arrow in FIG. 2A. do. After the sample is filled in a predetermined amount by the volume of the roofing device 50, the control valve 60 is switched to the position shown in Figure 2b.

As such, when the control valve 60 is switched to the position of FIG. 2B, the flow path inlet introduced into the roofing device 50 is blocked so that the sample no longer flows from the sample supply device 40 toward the roofing device 50. However, the inlet side of the roofing device 50 communicates with the flow path of the carrier gas storage tank 70, and the outlet side of the roofing device 50 communicates with the flow path of the sample analyzer (not shown). A carrier gas of 70 flows into the roofing device 50 along the dotted arrow direction of FIG. 2B to push the sample filled therein toward the sample analyzer. Therefore, a certain amount of the sample is sent to the sample analyzing apparatus in this process, so that the sample analyzing apparatus analyzes a certain amount of the sample, and thus the sample analyzing apparatus analyzes the sample without occurrence of tailing phenomenon.

As described above, when one type of sample is removed and distributed and then another sample is to be analyzed after the analysis is finished, the previous sample remaining in the apparatus of the present invention should be washed. In this case, the control valve 60 ) Is transferred to the control valve 60 in the state of switching to the position shown in FIG. 2C, the carrier gas passes through the control valve 60 and the roofing device 50 in sequence along the dotted arrow direction shown in FIG. 2C. As it is discharged, the device is cleaned by draining residual samples together.

On the other hand, in the embodiment of the present invention has been described for the manual operation of a series of processes, such as sample collection step, sample desorption step, the thermal desorption separation tube (20) in the state in which the thermal desorption separation tube (20) 20) is arranged in the target area to be collected, and then the first and second variable flow control valves 22 and 24 are adjusted, and the first open / close valve 28, the second open / close valve 29 and the first When the control unit automatically controls the opening / closing operation of the three open / close valves 43 and the switching operation of the control valve 60, the present invention may automatically collect, detach, dry, and dispense the sample to be automatically injected into the sample analysis device. have.

The present invention configured as described above does not need to use expensive equipment because it does not need to use expensive equipment because the sample to be analyzed is directly concentrated into the heat desorption separation tube without being liquefied and concentrated as a gas state, and then desorption by applying heat to the heat desorption separation tube. And maintenance cost can be reduced.

In addition, the present invention can prevent the tailing phenomenon during sample analysis in the sample analysis device by supplying the sample to the sample analysis device uniformly by a predetermined amount using a looping device having a simple structure, thereby obtaining a high reliability analysis result at low cost. There is a feature.

Claims (4)

A thermal desorption separation tube 20 for collecting and accommodating a sample of volatile organic compounds discharged from the atmosphere, water source or soil; A heating device (27) for supplying heat to the thermal desorption separation tube (20) to thermally desorb the sample collected therein from the thermal desorption separation tube; A sample dryer (30) for drying the sample by contacting the sample heat-desorbed in the thermal desorption separation tube (20) with a dry body; Desorption, which is connected to the thermal desorption separation tube 20, supplies a sample desorption gas into the thermal desorption separation tube 20, and is connected to the sample dryer 30 to supply a sample drying gas into the sample dryer 30. Dry gas storage tank (10); A sample supply device 40 for receiving and extruding the dried sample discharged from the sample dryer 30; A third opening / closing valve installed on the fourth connection line 32 for communicating the sample dryer 30 and the sample supply device 40 with each other to selectively open or close the flow path of the fourth connection line 32 ( 43); A roofing device 50 configured to receive a predetermined amount of a sample supplied from the sample supply device 40; A carrier gas storage tank (70) for storing and supplying a sample carrier gas which is pushed out of the sample contained in the roofing device (50) toward a sample analyzer; And It characterized in that it comprises a control valve 60 for communicating or blocking the sample supply device 40 and the roofing device 50 with each other and at the same time communicate or block the carrier gas storage tank 70 and the roofing device 50 with each other. Thermal desorption sample injection device of volatile organic compound analyzer. The method of claim 1, wherein the desorption-dry gas storage tank (10) and the desorption separation pipe 20 on the first connection line 21 to communicate with each other to supply or block the desorption gas toward the desorption separation pipe (20) The first opening / closing valve 28 and the first variable flow rate control valve 22 for adjusting the flow rate of the removable gas passing through the first opening / closing valve 28 are installed in series with each other, and the removable / dry gas storage tank ( 10) and a second open / close valve for supplying or blocking the sample dry gas from the removable / dry gas storage tank 10 toward the sample dryer 30 on the third connection line 31 communicating the sample dryer 30 with each other. And a second variable flow rate control valve (24) for variably controlling the amount of the sample dry gas supplied to the sample dryer (30) in series with each other. According to claim 1, wherein the control valve (60) is a thermal desorption sample injection device of the volatile organic compound analysis device, characterized in that consisting of a six-way rotary valve. The method of claim 1, wherein the roofing device 50 is a thermal desorption sample injection device of the volatile organic compound analysis device, characterized in that consisting of a spiral tube.