JP2004069578A - Gas chromatograph system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make up a sample-injecting system which has a flow sensor where no sample is accumulated thereon, and which can measure a pressure equal to that of a sample inlet section. <P>SOLUTION: The sample injecting system is made up so that the flow sensor, which measures the flow rate of carrier gas, is arranged in a carrier gas guide channel which guides the carrier gas to the sample inlet section, and a pressure sensor which measures a pressure of the sample inlet section, is arranged on the downstream side of the flow sensor and just ahead of the sample inlet section. In the sample injecting system, detected signals from the pressure sensor are input into a control section, and a split regulation valve is controlled by using processed control signals. <P>COPYRIGHT: (C)2004,JPO

Description

【数２】

【００１９】
【数３】

【００２０】
【数４】

【数５】

【００２１】
【数６】

【数７】

【００２２】
ｄ　　　　カラム内径［ｍｍ］
Ｆｃ　　　カラム流量［ｍｌ／ｍｉｎ］
Ｆｐ　　　セプタムパージ流量［ｍｌ／ｍｉｎ］
Ｆｓ　　　スプリット流量［ｍｌ／ｍｉｎ］
Ｆｔ　　　トータル流量（２５℃、１０１．３３ｋＰａ）［ｍｌ／ｍｉｎ］
Ｆｔ（０）　トータル流量（０℃、１０１．３３ｋＰａ）［ｍｌ／ｍｉｎ］
Ｌ　　　　カラム長［ｍ］
Ｎ　　　　窒素流量（０℃、１０１．３３ｋＰａ）［ｍｌ／ｍｉｎ］
Ｐｉ　　　入口圧力（ゲージ圧）［ｋＰａ］
Ｐｉａ　　入口圧力（絶対圧、Ｐｉ＋１０１．３３ｋＰａ）［ｋＰａ］
Ｐｏａ　　出口圧力（絶対圧）［ｋＰａ］
Ｐｒａ　　標準圧力（絶対圧）［ｋＰａ］
ＳＲ　　　スプリット比［−］
Ｔｃ　　　オーブン温度（温度［℃］＋２７３．１５）［Ｋ］
Ｔｒ　　　標準温度（２５℃、２９８．１５Ｋ）［Ｋ］
Ｖｃ　　　カラム線速度［ｃｍ／ｓ］
η　　　　粘度［μＰａ・ｓ］
【００２３】
【発明の効果】
本発明によるガスクロマトグラフの試料注入システムは、試料による各センサの汚染がなく、試料注入口部内の圧力を他の機器に影響されることなく直接的に検出することができるので、長期にわたって安定した性能を維持でき、測定結果の信頼性が高い。また、各センサの寿命も長くなるので、経済的な効果も期待できる。
【図面の簡単な説明】
【図１】本発明の実施例であるガスクロマトグラフ用検出器の構成図。
【符号の説明】
１…キャリヤーガス、２…バルブ、３…流量センサ、４…圧力センサ、５…試料注入口部、７…バルブ（流量調整器）、８…セプタムパージベント、９…バルブ（流量調整器）、１０…スプリット量調整バルブ、１１…スプリットベント、１２…分離カラム、１３…検出器、１４…制御部、１５…マイクロシリンジ、２１…キャリヤーガスの導入流路、２２…セプタムホルダ、２３…ヒートブロック、２４…外管ステンレス管、２５…ガラス内管、２６…セプタム、２７、２８…開口部、３１、３２…細管。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to sample introduction in a gas chromatograph for separating a substance and performing quantitative or qualitative analysis, and particularly to an injection system using a capillary column.
[0002]
[Prior art]
In a conventional apparatus, a pressure sensor or a pressure regulator is provided in a split flow path or a septum purge flow path in order to read an inlet internal pressure, that is, a separation column inlet pressure, to control the pressure inside the inlet. Was common. Since the split flow path or the septum purge flow path contains most or a part of the sample, the sample may accumulate on the pressure sensor or the pressure regulator and cause malfunction when used for a long period of time. Was. In this case, it is known to control a split amount adjusting valve provided downstream of the sample inlet, that is, in parallel with the separation column, by a detection signal detected by a pressure sensor. Further, the contents described in Japanese Patent Publication No. 5-2268 are known.
[0003]
[Problems to be solved by the invention]
The present invention considers that the problem of the prior art is that there is a fundamental problem in arranging a pressure sensor or a flow sensor or both in a flow path of a sample, and in the present invention, it is considered that the sample is accumulated. It is an object of the present invention to provide a sample injection system capable of providing a sensor in a non-existing flow path and measuring a pressure equal to the pressure of the sample injection port.
[0004]
The present invention has been made in consideration of the problem that the sample described in the section of the related art causes the sample to accumulate in the pressure sensor or the flow sensor and cause malfunction, and the gas chromatograph can be used stably for a long time. An object of the present invention is to provide a sample injection system for a graph.
[0005]
[Means for Solving the Problems]
A sample adjustment port for introducing a sample and a carrier gas, respectively, and a sample injection port to which a separation column is connected, wherein the sample adjustment port adjusts an appropriate amount of sample to be introduced into the separation column; and A septum purge valve for discharging impurities attached to the partition wall of the sample injection port to the outside is connected, and a sample injection system is provided in which a flow rate and a pressure of the carrier gas are measured and a detection signal is introduced into the control unit.
[0006]
Further, a flow sensor for measuring the flow rate of the carrier gas is provided in a carrier gas introduction flow path for introducing the carrier gas into the sample injection port, and the sample is provided immediately downstream of the sample injection port on the downstream side of the flow sensor. A pressure sensor for measuring the pressure of the inlet portion is provided, a detection signal from the pressure sensor is introduced to a control unit, and the split control valve is controlled by the processed control signal, so that the sample injection system is Be composed.
[0007]
The sample injection system is configured such that a detection signal from the flow sensor is introduced into a control unit, and a valve provided on the upstream side of the flow sensor on the carrier gas introduction flow path is controlled by the processed control signal. Is done.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a sample injection system for a gas chromatograph according to the present invention will be described with reference to an embodiment shown in FIG.
The sample injection system according to the present embodiment is configured as follows, with the sample injection port 5 as the center of the configuration.
The carrier gas 1 is introduced into the sample inlet 5 via the valve 2, the flow sensor 3 and the pressure sensor 4. The carrier gas 1 is connected to a cylinder (not shown), and a stainless steel pipe, which is an introduction flow path 21 for the carrier gas 1, is provided with a valve 2 and a flow sensor 3 for controlling a flow rate, and is provided downstream of the flow rate sensor 3. A pressure sensor 4 is provided near the upstream side of the sample inlet 5 on the side. No member such as a filter is provided between the pressure sensor 3 and the sample inlet 5.
[0009]
The sample inlet 5 includes a septum holder 22 and a heat block 23. A septum 26 is provided in the septum holder 22. The septum 26 penetrates the outer stainless steel tube 24 of the septum holder 22 and the center of the heat block 23. An inner glass tube 25 is provided. Both ends of the inner glass tube 25 are open, the upper end is an opening 27 that opens into the carrier gas introduction channel 21, and the lower end is an opening 28 that opens inside the lower end of the heat block 23. The heat block 23 is provided with a lid 29.
The split vent 11 is connected to a substantially central portion of the outer stainless steel pipe 24, and the split vent 11 is provided with a valve 9 and a split amount adjusting valve 10. Therefore, the split amount adjusting valve 10 is provided in parallel with the separation column 12 described later.
[0010]
The stainless steel pipe on the downstream side of the carrier gas introduction pipe 21 provided with the sample inlet 5 is a septum purge vent 8, and the stainless steel pipe is provided with a valve 7.
At the lower end of the outer stainless steel tube 24, a thin tube 31 constituting the separation column 12 is connected, and a thin tube 32 from the separation column 12 is connected to the detector 13.
The sample is injected into the carrier gas 1 from the needle that has been injected through the septum 26 with the microsyringe 15.
[0011]
The introduced carrier gas is split into two parts inside the sample inlet 5, and one of them is discharged out of the system through a septum purge vent 8 via a valve 7. This flow path is provided to prevent impurities eluted from the septum 26 from affecting the measurement. The other flows downward through the outer tube stainless steel tube 24, that is, the inside of the sample inlet 5 through the opening 27, and partly flows through the separation column 12 connected to the sample inlet 5. After being separated into each component, the detector 13 detects each component. The remaining part passes through the valve 9 and the split amount adjusting valve 10 and is discharged from the split vent 11 to the outside of the system. Here, the valve 2 is controlled by the control unit 14 based on the information of the flow sensor 3, and is controlled to have a predetermined flow rate. Further, the split amount adjusting valve 10 is controlled by the control unit 14 based on information from the pressure sensor 4, and the split amount adjusting valve 10 controls the pressure inside the sample inlet 5, that is, the inlet pressure of the separation column 12 to a predetermined pressure. Is controlled so that
[0012]
As shown in FIG. 1, respective detection signals from the flow sensor 3 and the pressure sensor 4 are input to the control unit 14 (computer processing device), and the control signal (processing signal) based on the detection signal from the flow sensor 3 controls the flow control. Is controlled, and the split amount adjusting valve 10 and the valve 9 are controlled by a control signal (processing signal) based on the detection signal of the pressure sensor 4.
[0013]
As in this case, the pressure sensor 4 is provided downstream of the flow rate sensor 3 and near the upstream of the sample inlet 5, and the split amount adjusting valve 10 is provided downstream of the sample inlet 5. is important. When the flow sensor 3 is provided on the downstream side of the pressure sensor 4, the pressure sensor 4 detects the pressure at the position of the flow sensor 3, and detects the accurate pressure equivalent to the pressure in the sample inlet 5. You don't. That is, the pressure in the sample inlet 5 cannot be read.
[0014]
As described above, the pressure sensor 4 is provided in the vicinity of the upstream of the sample injection port 5, and no device or means is provided between the pressure sensor 4 and the sample injection port 5 directly. To detect the pressure. Then, it is important to control the split amount adjustment valve 10 based on the signal obtained by the configuration arranged as described above.
[0015]
The reason why the split amount adjusting valve 10 is provided downstream of the sample inlet 5 is that the amount of the sample in the sample inlet 5 can be directly controlled. In the method in which the split adjustment valve 10 is provided on the upstream side of the sample injection port 5, the sample is unnecessarily retained in the sample injection port 5 due to control delay, which is not desirable.
[0016]
As described above, according to the present embodiment, the pressure in the sample inlet 5 is provided downstream of the flow sensor 3 and near the upstream of the sample inlet 5 so that the pressure in the sample inlet 5 is affected by the presence of the flow sensor 3. Instead, the split amount adjustment valve 10 provided downstream of the sample inlet 5 is controlled by a control signal generated based on a detection signal from the pressure sensor 4 which is directly detected. .
[0017]
The sample is injected through the septum 26 by the microsyringe 15. In this embodiment, since the positions of the flow rate sensor 3 and the pressure sensor 4 are set upstream of the sample introduction part, the sample is not filled with the above-mentioned sensor 3. 4. Does not contaminate.
The inlet pressure of the separation column 12 and the total flow rate flowing into the sample inlet 5 can be determined by the following equations (1) to (7) based on the laws of fluid dynamics.
[0018]
Calculation of column inlet pressure [Equation 1]

(Equation 2)

[0019]
[Equation 3]

[0020]
(Equation 4)

(Equation 5)

[0021]
(Equation 6)

(Equation 7)

[0022]
d Column inner diameter [mm]
Fc column flow rate [ml / min]
Fp septum purge flow rate [ml / min]
Fs split flow rate [ml / min]
Ft total flow rate (25 ° C, 101.33 kPa) [ml / min]
Ft (0) Total flow rate (0 ° C, 101.33 kPa) [ml / min]
L Column length [m]
N Nitrogen flow rate (0 ° C, 101.33 kPa) [ml / min]
Pi inlet pressure (gauge pressure) [kPa]
Pia inlet pressure (absolute pressure, Pi + 101.33 kPa) [kPa]
Poa Outlet pressure (absolute pressure) [kPa]
Pra Standard pressure (absolute pressure) [kPa]
SR split ratio [-]
Tc oven temperature (temperature [° C] +273.15) [K]
Tr standard temperature (25 ° C, 298.15K) [K]
Vc Column linear velocity [cm / s]
η viscosity [μPa · s]
[0023]
【The invention's effect】
The sample injection system of the gas chromatograph according to the present invention is stable for a long period of time because there is no contamination of each sensor by the sample and the pressure in the sample inlet can be directly detected without being affected by other devices. Performance can be maintained and measurement results are highly reliable. Further, since the life of each sensor is prolonged, an economic effect can be expected.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a gas chromatograph detector according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Carrier gas, 2 ... Valve, 3 ... Flow rate sensor, 4 ... Pressure sensor, 5 ... Sample injection port, 7 ... Valve (flow rate regulator), 8 ... Septum purge vent, 9 ... Valve (flow rate regulator), DESCRIPTION OF SYMBOLS 10 ... Split amount adjustment valve, 11 ... Split vent, 12 ... Separation column, 13 ... Detector, 14 ... Control part, 15 ... Micro syringe, 21 ... Carrier gas introduction flow path, 22 ... Septum holder, 23 ... Heat block , 24: outer tube stainless steel tube, 25: glass inner tube, 26: septum, 27, 28: opening, 31, 32: thin tube.

Claims (2)

A sample injection port to which a sample and a carrier gas are respectively introduced and to which a separation column is connected, wherein an appropriate sample amount is introduced into the separation column in parallel with the separation column at the sample injection port; And a septum purge valve for discharging impurities attached to the partition wall of the sample inlet to the outside so that the flow rate and pressure of the carrier gas are measured and a detection signal is introduced to the control unit. In a gas chromatograph apparatus equipped with a sample injection system,
A carrier gas introduction flow path for introducing the carrier gas into the sample inlet, a flow sensor for measuring the flow rate of the carrier gas, and the sample inlet on the downstream side of the flow sensor just before the sample inlet; The sample injection system is configured such that a pressure sensor that measures the pressure of the unit is provided, a detection signal from the pressure sensor is introduced to a control unit, and the split control valve is controlled by the processed control signal. A gas chromatograph device. 2. The method according to claim 1, wherein a detection signal from the flow sensor is introduced into a control unit, and a valve provided upstream of the flow sensor on the carrier gas introduction flow path is controlled by the processed control signal. A gas chromatograph device comprising a sample injection system.

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