CN105527335A - Photoionization detector - Google Patents
Photoionization detector Download PDFInfo
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- CN105527335A CN105527335A CN201610073075.1A CN201610073075A CN105527335A CN 105527335 A CN105527335 A CN 105527335A CN 201610073075 A CN201610073075 A CN 201610073075A CN 105527335 A CN105527335 A CN 105527335A
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- electrode
- photoionization detector
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/64—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using wave or particle radiation to ionise a gas, e.g. in an ionisation chamber
Abstract
A photoionization detector comprises an ionization chamber and an ultraviolet lamp, wherein an emitting electrode and a collecting electrode are arranged in the ionization chamber and are coaxially arranged, and the collecting electrode is a hollow cylinder body and surrounds the emitting electrode; a grounding electrode is further arranged between the emitting electrode and the ultraviolet lamp in the ionization chamber for shielding external electromagnetic interference. According to a three-electrode structure, the grounding electrode is mainly used for shielding electromagnetic interference of a driving power supply and the environment; with the design of the parallel structure of the collecting electrode and the emitting electrode, the distance between the collecting electrode and the emitting electrode is greatly reduced to 0.2-1 mm from 2-3 mm in a traditional structure, one-time electron capture efficiency is improved, and the detection sensitivity is greatly improved.
Description
Technical field
The present invention relates to a kind of gas chromatographicanalyzer device, further relate to a kind of photoionization detector (PID).
Background technology
In the gas on-sites such as environmental air quality monitoring, the monitoring of equipment environment, industrial pollution, chemical industry leakage, chemical warfare agent diagnosis detect fast, need a large amount of high-sensitivity miniature detecting devices to realize on-the site analysis or on-line monitoring.
In detector, photoionization detector has the features such as sensing range is wide, detection limit is low, analysis speed is fast, is extremely important in chromatographic field and widely used a kind of detecting device.But because environmental sample is generally containing water vapor, and moisture is very large on the impact of PID detecting device detection sensitivity, and can reduce its sensitivity 1-2 order of magnitude, therefore, how remove the water vapor in sample, be a key factor prepared by PID detecting device.In addition, in PID detecting device, the electromagnetic interference (EMI) that its vacuum ultraviolet lamp driving power source produces can have a strong impact on the ground unrest of detecting device, baseline size and baseline wander.
In existing photoionization detector, in the moisture in noise reduction and removal sample, there is very large drawback.In addition, due to metal electrode be subject to UV-irradiation time, photoelectric effect can be produced, what wherein collector was subject to has the greatest impact, and traditional PI D detecting device is when shielding collector, generally make up with the distance of sacrificing between collector and emitter, but excessive distance, electron capture efficiency can be reduced again and increase electron recombination efficiency, thus reducing the sensitivity of PID detecting device.
Summary of the invention
In view of this, the object of the invention is to propose a kind of photoionization detector, to overcome the above problem.
To achieve these goals, the invention provides a kind of photoionization detector, comprise ionization chamber and ultraviolet lamp, in described ionization chamber, be provided with emitter and collector, wherein,
Described emitter and the coaxial setting of collector, described collector is hollow cylinder and is surrounded on described emitter; And
In described ionization chamber, between described emitter and ultraviolet lamp, be provided with ground-electrode, to shield external electromagnetic interference.
According to a kind of specific embodiments of the present invention, the distance between described emitter and collector is 0.1-1mm.
According to a kind of specific embodiments of the present invention, described photoionization detector comprises dehydrating unit further, makes gas to be detected by entering described ionization chamber again after described dehydrating unit.
According to a kind of specific embodiments of the present invention, described ground-electrode is circular, and setting coaxial with described emitter.
According to a kind of specific embodiments of the present invention, in the side of the relative ultraviolet lamp of described ground-electrode and the side of relative transmission pole, be respectively arranged with insulating element and/or plating insulation course.
According to a kind of specific embodiments of the present invention, described ionization locular wall offers multiple exhaust emissions through hole further.
According to a kind of specific embodiments of the present invention, the cylinder interior diameter of described collector is 4-5mm.
According to a kind of specific embodiments of the present invention, the interior diameter of described ground-electrode is 2-4mm.
According to a kind of specific embodiments of the present invention, described emitter is provided with insulator cap.
According to a kind of specific embodiments of the present invention, described collector and described emitter are positioned at the same side of described ground-electrode.
According to above technical scheme, the beneficial effect of photoionization detector of the present invention is:
(1) by further arranging ground-electrode, form three-electrode structure, wherein ground-electrode mainly can carry out the electromagnetic interference (EMI) in shield guard power supply and environment;
(2) by design collector and emitter parallel organization, greatly reduce distance between the two, reduce to 0.2-1mm from the 2-3mm of traditional structure, increase electronics capture rate, significantly improve detection sensitivity;
(3) by adopting columniform collector, the pond volume of PID ionization chamber can be effectively reduced, improve the response speed of detecting device, reduce flow rate of carrier gas, further, adopt insulation course shielding collector, well prevent collector to be subject to the direct projection of ultraviolet light, and production background noise, increase baseline noise;
(4) by designing and being integrated with the dehumidifier self with Fast Heating, the water vapor in sample can be removed, the absorption of ionization chamber to sample can also be reduced in addition, improve detection sensitivity;
(5) by ionization locular wall offers multiple exhaust emissions through hole further, adopt the exhaust emissions mode of porous pass-through type, sample is after ionization, can be discharged rapidly, decrease electron recombination rate, decrease sample retention and the double ionization produced simultaneously, reduce baseline wander, improve the resolution of detecting device; PID detecting device after upper design, its minimal detectable concentration can reach below 1ppb, and resolution is less than 2ppb.
Accompanying drawing explanation
Fig. 1 is the schematic cross-section of the embodiment of the present invention 1.
Fig. 2 is the schematic appearance of collector in the embodiment of the present invention 1.
Fig. 3 is schematic appearance bottom ionization chamber in the embodiment of the present invention 1.
Fig. 4 is the partial cross section schematic diagram of the embodiment of the present invention 1 containing dehydrating unit.
Embodiment
The invention provides a kind of photoionization detector, comprise ionization chamber and ultraviolet lamp, emitter and collector are set in ionization chamber, wherein,
Described emitter and the coaxial setting of collector, collector is hollow cylinder and is surrounded on described emitter;
In ionization chamber, between described emitter and ultraviolet lamp, ground-electrode is set further, to shield external electromagnetic interference.
For the distance between emitter and collector, distance in prior art between electrode is 2-4mm, distance between the preferred emitter of the present invention and collector two electrode is 0.1-1mm, this setting makes two interelectrode distances significantly reduce, thus the dead volume of ionization chamber is decreased, improve electronics capture rate, thus improve detection sensitivity, in addition, also significantly flow rate of carrier gas can be reduced, the flow rate of carrier gas of traditional PI D can be reduced to 3-10ml/min from 30-50ml/min, be conducive to the miniaturization of PID detecting device.
For ground-electrode, preferably dull and stereotyped and setting coaxial with emitter, preferred ground-electrode is circular further; Ground electrode materials can be common conductive material, preferably stainless steel, copper or other metal; Preferably, the cylinder interior diameter of described collector is 2-4mm, overall diameter 6-15mm, thick 0.1-1mm, and preferred interior diameter is 1-3mm further, and overall diameter 6-8mm, thick 0.3-0.8, most preferred is interior diameter 3mm, overall diameter 8mm, high 0.3mm.
For collector, it is hollow cylinder structure, and material can be common conductive material, preferably stainless steel, copper or other metal; Preferably, the cylinder interior diameter of described collector is 4-5mm, overall diameter 5-8mm, high 2-5mm, and preferred interior diameter is 4-5mm further, and overall diameter 6-7mm, high 3-4mm, most preferred is interior diameter 4.5mm, overall diameter 6mm, high 3mm.
Emitter adopts cylindrical structural, and it prepares material is stainless steel, copper or other metal material, and the interior diameter of cylinder is 0.5-2mm, preferred 0.8mm, and overall diameter is 2-4.5mm, preferred 4mm, height 2-4mm, preferred 2.5mm.Described collector and described emitter are positioned at the same side of described ground-electrode.
Alternative, described ionization locular wall offers multiple exhaust emissions through hole further, and its through-hole diameter is preferably the distance between collector and emitter.
Alternative, described emitter is provided with insulator cap, insulator cap adopts truncated cone-shaped structure, it prepares material is teflon (PTFE), polyetheretherketone (PEEK) or other insulating material, bottom its round platform, the external diameter of circle is larger than the external diameter of emitter, can shield the irradiation of emitter by ultraviolet light.
Alternative, in the side of the relative ultraviolet lamp of described ground-electrode and the side of relative transmission pole, insulating element and/or plating insulation course are set respectively, by adopting insulation course shielding collector, collector is well prevented to be subject to the direct projection of ultraviolet light, and production background noise, increase baseline noise.Insulating element or insulation course, adopt cirque structure, it prepares material is teflon (PTFE), polyetheretherketone (PEEK) or other insulating material, the internal radius of insulation course or insulating element is less than the internal diameter of ground-electrode annulus, energy bonding electrode is by the irradiation of ultraviolet light, thickness is 0.2mm, and the internal radius of insulation course or insulating element is consistent with the internal diameter of ground-electrode annulus, can shield the irradiation of collector by ultraviolet light.
Alternative, described photoionization detector comprises dehydrating unit further, makes gas to be detected by entering described ionization chamber again after described dehydrating unit.Described dehydrating unit is common dehumidifier, the packing material preferably absorbent material of dehumidifier, and preferred packing material is silica gel further.
For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with embodiment 1, and with reference to accompanying drawing, the present invention is described in further detail.
Embodiment 1
As shown in Figure 1, a photoionization detector for integrated dehumidifier, this detecting device comprises: the vacuum UV lamp 1 of external diameter 6mm, ionization chamber 8, emitter 3, collector 4, ground-electrode 2, insulator cap 7, chromatographic column 12, pass-through type offgas outlet 9 and uviol lamp driving power.The two ends up and down of detecting device are fixed respectively by the first pressure ring 13 and the second pressure ring 14.
Wherein, ground-electrode 2, collector 4, emitter 3 and insulator cap 7 are on the same axis, ground-electrode 2 shields the electromagnetic noise of vacuum UV lamp 1 driving circuit, and emitter 3 is positioned at the axis of collector 4, and be arranged in parallel with collector 4 and distance is between the two 0.1-1mm.
Emitter 3 adopts cylindrical structural, and it prepares material is stainless steel, and the interior diameter of cylinder is 0.5-2mm, and overall diameter is 2-4.5mm, height 2-4mm.Emitting electrode is provided with insulator cap 7, and insulator cap 7 adopts truncated cone-shaped structure, and it prepares material is teflon, and bottom its round platform, the external diameter of circle is slightly larger than the external diameter of emitter, can shield the irradiation of emitter by ultraviolet light.
Ground-electrode 2 adopts cirque structure, and it prepares material is stainless steel, and the interior diameter of cylinder is 2-4mm, and overall diameter is 6-15mm, thickness 0.3mm.Ground-electrode 2 both sides 2 are provided with insulation course, first insulation course 5 and the second insulation course 6, adopt cirque structure, it prepares material is teflon, the internal radius of the first insulation course 5 is less than the internal diameter of ground-electrode annulus, and energy bonding electrode is by the irradiation of ultraviolet light, and thickness is 0.2mm, the internal radius of the second insulation course 6 is consistent with the internal diameter of ground-electrode annulus, can shield the irradiation of collector by ultraviolet light.
As shown in Figure 2, collector 4 adopts cylindrical structural, and it prepares material is stainless steel, and the interior diameter of cylinder is 6mm, high 2-5mm.In addition collector 4 shields through insulation course 2, ultraviolet light cannot direct projection on collector, thus greatly reduce the electronic interferences that photoelectric effect is brought, reduce ground unrest.
As shown in Figure 3, be provided with offgas outlet 9 bottom ionization chamber, adopt the exhaust emissions mode of porous pass-through type, sample, after ionization, can be discharged rapidly.
As shown in Figure 4, the integrated dehumidifier 10 of photoionization detector, fills efficient absorbent material 11 in dehumidifier 10, efficiently can remove water vapor, improves detection sensitivity.Gas to be detected after chromatographic column 12, then removes moisture by dehumidifier 10, then enters ionization chamber 8 and detects.
Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. a photoionization detector, comprises ionization chamber and ultraviolet lamp, is provided with emitter and collector, it is characterized in that in described ionization chamber,
Described emitter and the coaxial setting of collector, described collector is hollow cylinder and is surrounded on described emitter; And
In described ionization chamber, between described emitter and ultraviolet lamp, be provided with ground-electrode, to shield external electromagnetic interference.
2. photoionization detector according to claim 1, is characterized in that, the distance between described emitter and collector is 0.1-1mm.
3. photoionization detector according to claim 1, is characterized in that, described photoionization detector comprises dehydrating unit further, makes gas to be detected by entering described ionization chamber again after described dehydrating unit.
4. photoionization detector according to claim 1, is characterized in that, described ground-electrode is circular, and setting coaxial with described emitter.
5. photoionization detector according to claim 1, is characterized in that, in the side of the relative ultraviolet lamp of described ground-electrode and the side of relative transmission pole, is respectively arranged with insulating element and/or plating insulation course.
6. photoionization detector according to claim 1, is characterized in that, described ionization locular wall offers multiple exhaust emissions through hole further.
7. photoionization detector according to claim 1, is characterized in that, the cylinder interior diameter of described collector is 4-5mm.
8. photoionization detector according to claim 4, is characterized in that, the interior diameter of described ground-electrode is 2-4mm.
9. photoionization detector according to claim 1, is characterized in that, described emitter is provided with insulator cap.
10. photoionization detector according to claim 1, is characterized in that, described collector and described emitter are positioned at the same side of described ground-electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610073075.1A CN105527335A (en) | 2016-02-02 | 2016-02-02 | Photoionization detector |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610073075.1A CN105527335A (en) | 2016-02-02 | 2016-02-02 | Photoionization detector |
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| CN201610073075.1A Pending CN105527335A (en) | 2016-02-02 | 2016-02-02 | Photoionization detector |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108776169A (en) * | 2018-03-23 | 2018-11-09 | 无锡格林通安全装备有限公司 | A kind of PID gas sensors that humidity can be inhibited to interfere |
| WO2020226568A1 (en) * | 2019-05-07 | 2020-11-12 | R2Cd Holdings Pte. Ltd. | Dehumidifier and photoionization detecting device with dehumidifying function |
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| CN1294750A (en) * | 1998-01-08 | 2001-05-09 | 利通系统有限公司 | Magnetron |
| WO2006028402A1 (en) * | 2004-09-01 | 2006-03-16 | Yuri Petrovich Gorbachev | Analytic head for detecting trace contaminants in gases |
| CN1818633A (en) * | 2006-03-17 | 2006-08-16 | 中国科学院安徽光学精密机械研究所 | Portable ionization chamber of photoionization detector |
| CN1934442A (en) * | 2004-03-31 | 2007-03-21 | 矿井安全装置公司 | Photoionization detector |
| CN101308125A (en) * | 2007-05-18 | 2008-11-19 | 华瑞科学仪器(上海)有限公司 | Photoionization detector, gas-chromatography detection system and chromatographic detector method |
| CN103575839A (en) * | 2012-07-18 | 2014-02-12 | 中国科学院电子学研究所 | High sensitivity photoionization detector |
| CN103691318A (en) * | 2014-01-07 | 2014-04-02 | 延边大学 | Micro-scale substance separating method and capillary column transverse eletrochromatography separating device |
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2016
- 2016-02-02 CN CN201610073075.1A patent/CN105527335A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1294750A (en) * | 1998-01-08 | 2001-05-09 | 利通系统有限公司 | Magnetron |
| CN1934442A (en) * | 2004-03-31 | 2007-03-21 | 矿井安全装置公司 | Photoionization detector |
| WO2006028402A1 (en) * | 2004-09-01 | 2006-03-16 | Yuri Petrovich Gorbachev | Analytic head for detecting trace contaminants in gases |
| CN1818633A (en) * | 2006-03-17 | 2006-08-16 | 中国科学院安徽光学精密机械研究所 | Portable ionization chamber of photoionization detector |
| CN101308125A (en) * | 2007-05-18 | 2008-11-19 | 华瑞科学仪器(上海)有限公司 | Photoionization detector, gas-chromatography detection system and chromatographic detector method |
| CN103575839A (en) * | 2012-07-18 | 2014-02-12 | 中国科学院电子学研究所 | High sensitivity photoionization detector |
| CN103691318A (en) * | 2014-01-07 | 2014-04-02 | 延边大学 | Micro-scale substance separating method and capillary column transverse eletrochromatography separating device |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108776169A (en) * | 2018-03-23 | 2018-11-09 | 无锡格林通安全装备有限公司 | A kind of PID gas sensors that humidity can be inhibited to interfere |
| CN108776169B (en) * | 2018-03-23 | 2024-02-06 | 无锡格林通安全装备有限公司 | PID gas sensor capable of inhibiting humidity interference |
| WO2020226568A1 (en) * | 2019-05-07 | 2020-11-12 | R2Cd Holdings Pte. Ltd. | Dehumidifier and photoionization detecting device with dehumidifying function |
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Application publication date: 20160427 |