CN2439025Y - Dynamic pre-concentrating apparatus for gas sample - Google Patents
Dynamic pre-concentrating apparatus for gas sample Download PDFInfo
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- CN2439025Y CN2439025Y CN 00210483 CN00210483U CN2439025Y CN 2439025 Y CN2439025 Y CN 2439025Y CN 00210483 CN00210483 CN 00210483 CN 00210483 U CN00210483 U CN 00210483U CN 2439025 Y CN2439025 Y CN 2439025Y
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Abstract
The utility model relates to a dynamic pre-concentrating device for gas samples, which is composed of a quantitative tube, a six-way sampling valve, an analytical column, a four-way cutting valve and a concentrating column, wherein, one end of the quantitative tube is connected to an inlet of the analytical column via the six-way sampling valve; an outlet of the analytical column is connected with an outlet of the concentrating column via the four-way cutting valve; an inlet of the concentrating column is connected with the other end of the quantitative tube via the six-way sampling valve. A sample is connected with both ends of the quantitative tube via the six-way sampling valve. Carrier gas is respectively connected with the analytical column and the concentrating column via the four-way cutting valve. The utility model can concentrate gaseous hydrocarbon of C2 and above C2 under the room temperature condition, and simultaneously obtain a high concentration ratio under a minor sample size to meet needs of high sensitive analysis at occasions of fast concentration and limited sample sizes.
Description
The utility model relates to the analytical technology of trace gas component, and a kind of small size dynamic Pre-concentration Method of Gas Sample is provided especially.
The analysis of trace gas component is a very important problem in current analytical chemistry field always, be example only with the environment aspect, along with the growing interest of people to environmental problem, every year, the research report about mensuration, automobile and the diesel engine vent gas analysis of components etc. of Atmospheric Trace organic contaminant all had pieces of writing up to a hundred.The development of trace gas analysis technology depends on the appearance of high-sensitivity analysis instrument, but more is that high efficiency enrichment method technology is being brought into play key effect.
The enrichment method of gaseous sample is meant and utilizes the whole bag of tricks that the component content to be measured in the sample is improved the sample pretreatment process of removing most main components simultaneously.The enrichment method method of gaseous sample has a lot, at present main use solution absorption method, cryogenic trapping method and solid absorption method arranged.
Gaseous sample beneficiation technologies commonly used at present all exists many disadvantages and deficiency inevitably: solution absorption method is restricted range of application because of the interference that has big solvent peak; The cryogenic trapping method is not only assembled a large amount of later stratographic analyses of water vapor influence easily, and use cold-trap complicated operation, waste time and energy, be not suitable for the sample concentration analysis of (as strong vibration, high-temperature, high acceleration and golden automation mechanized operation) under process on-line analysis, open-air analysis and the specific condition etc.; Normal temperature absorption in the solid absorption method can avoid using cold-trap, and is simple to operate, easily be automated, but it has the low boiling component easily to lose, and is not suitable for the shortcoming of lower carbon number hydrocarbons enrichment.
In addition, these enrichment methods all need bigger sample size unlimitedly, and this not only causes the sampling time long, and the time of desorption is also long, and then cause entering the solute band broad of chromatogram, and minimum detects problems such as concentration rising.In addition, for the analysis of the limited occasion of sample, as eudiometry etc. in the on-line analysis of tracer gas in the large-scale power transformer oil, the spacecraft module, existing technology all can not realize required enrichment multiple.
The purpose of this utility model provides a kind of dynamic pre-concentration device of gaseous sample, it can be realized at ambient temperature to C2 and the enrichment of each gaseous hydrocarbon more than the C2, simultaneously can under less sample size, obtain higher cocnentration factor, to satisfy the highly sensitive analysis of fast enriching and the limited occasion of sample size.
The utility model provides a kind of dynamic pre-concentration device of gaseous sample, by quantity tube (7), six-way injection valve (8), analytical column (9), four-way cutting valve (10) and evaporating column (11) are formed, one end of quantity tube (7) passes through six-way injection valve, (8) connect the inlet of analytical column (9), the outlet of analytical column (9) is cut valve (10) by four-way and is linked to each other with detecting device (12), evaporating column (11) inlet joins by the other end of six-way injection valve (8) with quantity tube (7), sample introduction connects the two ends of quantity tube (7) by six-way injection valve (8), and carrier gas is cut valve (10) by four-way and linked to each other with evaporating column (11) with analytical column (9) respectively.See accompanying drawing 1.
Principle of work of the present utility model is as follows:
During beginning, the sample that carrier gas is promoting certain volume enters (as shown in Figure 2) in the normal temperature evaporating column, and sample is the process of a pre-separation in the absorption essence of evaporating column.Selecting on the suitable adsorbent, trace components to be measured has stronger reservation than main body component.So distillate when most of main body component, and component to be measured is slow when mobile in evaporating column, has just obtained enrichment to a certain degree.When the bands of a spectrum forward position of component to be measured is about to distillate evaporating column, rotation cutting valve, blowback is also heated evaporating column (as shown in Figure 3).Component desorption to be measured under the high temperature, bands of a spectrum snap back move and because of being compressed along thermograde negative on the moving direction, enter analytical column until flowing out this post.Therefore whole dynamic pre-concentration process can be divided into three phases, i.e. normal temperature enrichment stage, the cutting blowback moment, desorption by heating stage.See Fig. 4,5,6 respectively in the reservation situation of each stage determinand in evaporating column.
There are several important links playing a part key in the said process.At first be the selection of evaporating column stationary phase: after sample entered evaporating column, it was carrying out the process of pre-separation and enrichment really.Utilize adsorbent to make wherein main body component keep extremely weak or do not keep (capacity factor measure K0 ' ≈ 0) substantially, and that the component to be measured in the sample keeps is very strong, be i.e. capacity factor measure K the difference of sample retention properties
1' very big.After most of main body component distillated, component to be measured had just obtained enrichment in evaporating column, and the multiple of its enrichment is K
1'+1.During the blowback desorption, the temperature moment rising of evaporating column, adsorbent reserve capability to component to be measured under this high temperature descends significantly, and capacity factor measure levels off to 0, so the quick desorption of component to be measured distillates evaporating column.Therefore ideal evaporating column stationary phase should be under the normal temperature component to be measured to be had stronger reservation, and the not really high adsorbent of desorption temperature.As C
2The TDX-01 carbon molecular sieve adsorbent of hydrocarbon is at room temperature to C
2Hydrocarbon has stronger reservation (capacity factor measure K '＞40), and desorption temperature (K '≤1) is below 220 ℃.
Secondly, cutting blowback thermal desorption technology is dynamically playing an important role in the pre-concentration process.
(1) overwhelming majority when the main body component distillates from evaporating column, and component bands of a spectrum to be measured forward position begins to cut blowback when being about to occur.By the time of strictness control cutting blowback, both can avoid component to be measured on evaporating column, to penetrate, cause the loss of the recovery, guaranteed that again residual main body component peak hangover can not produce interference to component to be measured.
(2) when material to be measured is several components, they are also carrying out pre-separation each other when concentrating on-column enrichment process.The component that has is a little a little less than stick effect on the adsorbent, and translational speed is very fast relatively, has gone to the position of front; Keep strong slightly component and then fallen the back, so the solute band that is adsorbed broadening to some extent just.After the cutting blowback, the solute band that is adsorbed begins oppositely to move, and fireballing component becomes the position that is in the back, and in front slow-footed, the process of desorption from evaporating column, solute band has just obtained compression to a certain degree.
(3) constantly, the pressure of evaporating column has experienced once sudden change, has formed the unstable state of moment, makes carrier gas " surge " go into evaporating column until reaching stable state, specifically shown in Fig. 7,8 in the cutting blowback.
As seen from the figure, before the cutting carrier gas be earlier by analysis post (A → B), quantity tube then enter evaporating column (C → D), pressure relation everywhere has:
P
in=P
A＞P
B=P
C＞PD=P
out
The carrier gas of cutting back is oppositely moved, become earlier through evaporating column (enter again behind the D → C) analytical column (B → A), everywhere pressure relation has when reaching stable state:
P
in=P
D＞P
C=P
B＞P
A=P
out
Therefore in the moment of cutting blowback, because P
In＞P
D, carrier gas " surge " is gone into the D end up to reaching balance.The transient of this section moment not only makes the solute band translational speed accelerate, and desorption time shortens, and also can form certain velocity gradient on evaporating column and has compressed the solute band width.
(4) be the thermal desorption process at last, its key is to reduce the width of desorption bands of a spectrum as far as possible, makes sample enter analytical column with " stopper " form.When high temperature desorption from evaporating column,, but still have the broadening of the solute band that causes because of the difference that keeps because of all component retentions all reduce to make whole desorption rate very fast significantly.Some document adopt cold column cap to focus on or secondary desorption mode be exactly after relying on the minimum cold-trap of internal volume with desorption the solute band of broad be frozen into " stopper " shape, instant vaporization enters chromatographic system again.Dynamic Pre-concentration Method had not both used cold-trap to focus on, and did not have the secondary desorption apparatus again, but utilized the thermograde that is rapidly heated and bears to reduce the desorption spectral bandwidth effectively.Specific as follows:
(A) be rapidly heated: in desorption process, heating rate is slow, can make desorption bands of a spectrum broadening, finally can cause the analytical spectra peak width big, degradation problem under the minimum detectable quantity.When programming rate was fast, the desorption bands of a spectrum narrowed down (half-peak breadth 2-3 second), laid a good foundation than enrichment for realizing that finally small samples is highly enriched.
(B) Fu thermograde: when evaporating column was heated, the speed that makes edge behind the bands of a spectrum can realize the further compression of bands of a spectrum always greater than the speed in forward position in such transient.
In sum, the dynamic pre-concentration device of the utility model combines blowback one peak cutting technique and the normal temperature thermal desorption technology of adsorbing dexterously, makes whole enrichment process remain a kind of continuity and dynamic; The thermograde that forms is had a mind in its selection by suitable adsorbent simultaneously, cutting blowback operation to compression, the technology that is rapidly heated of solute band and when adding thermal desorption, make that desorption rate is fast and solute band is narrow, and then guaranteed under less sample size, to obtain higher cocnentration factor.Below by embodiment in detail the utility model is described in detail.
Accompanying drawing 1 is the dynamic pre-concentration schematic diagram of device of small size gaseous sample.
Accompanying drawing 3 is the process flow diagram of dynamic pre-concentration blowback desorption stage of small size gaseous sample.
Accompanying drawing 4 is t
iReserving model (the t of moment determinand in evaporating column
iBe arbitrfary point in the normal temperature enrichment stage)
Accompanying drawing 5 is t
cReserving model (the t of moment determinand in evaporating column
cBe the cutting blowback moment)
Accompanying drawing 6 is t
jReserving model (the t of moment determinand in evaporating column
jBe desorption by heating arbitrfary point in the stage)
Accompanying drawing 7 is small size gaseous sample dynamic pre-concentration absorption phase pressure change and the signal of carrier gas flow direction mark.
Accompanying drawing 8 is pressure change of dynamic pre-concentration blowback desorption stage of small size gaseous sample and the signal of carrier gas flow direction mark.
Accompanying drawing 9 is without the lower carbon number hydrocarbons spectrogram of enrichment.
Lower carbon number hydrocarbons spectrogram after accompanying drawing 10 enrichments.
Accompanying drawing 11 is the interior desorption spectrograms that column temperature are heated to 250 ℃ in 25 seconds.
Accompanying drawing 12 is the interior desorption spectrograms that column temperature are heated to 250 ℃ in 6 seconds.
Embodiment 1
Instrument and sample gas
Last 1102 gas chromatographs (fid detector) the Shanghai analytical instrument factory that divides
Gas manual six leads to decides robotization research institute of volume sampling valve the Ministry of Chemical Industry
PMF-1-4 plane four-way cutting valve temperature peak analytical instrument factory
GZD-1 low-voltage/big current flow heats power supply Beijing nova power supply factory
AI708 temperature measuring set Xiamen space photoelectron technology research institute
TL9900 chromatographic data workstation Beijing Tai Li Electronics Co., Ltd.
Operating conditions
Evaporating column: 10cm * 1mmI.D. fills out 80-100 order TDX-01, temperature: room temperature.
Analytical column: 2m * 1mm I.D., fill out 100-120 order GDX-502, temperature: 30 ℃ of permanent 7.5min rise to 100 ℃ with 25 ℃/min, permanent again 5min.
Utilize dynamic Pre-concentration Method, the lower carbon number hydrocarbons sample has been carried out enrichment (10 milliliters of sample sizes), and compare, the results are shown in Figure 9,10 with conventional analysis (0.1 milliliter of sample size) without enrichment.Sample peak 1. ethene wherein; 2. ethane; 3. acetylene; 4, propane; 5. isobutane; 6. normal butane.
The ordinate of comparison diagram 9,10, can find out: utilize small size gaseous sample dynamic Pre-concentration Method, can obtain nearly 100 times concentration effect under 10 milliliters sample size, the ratio number of peak area also is about 100 (seeing Table 1).Compare the horizontal ordinate of two spectrograms simultaneously, find: the enrichment that utilizes the gaseous sample dynamic Pre-concentration Method to be done is analyzed and has only been used 5 minutes than conventional analysis more, and this is to the used time of desorption overall process from sample introduction.Deduct during this period of time, the retention time of two spectrograms is basic identical.
Table 1 is directly analyzed and the component peak area value is analyzed in enrichment
Table 3.1 The value of peak area of direct analysis and concentrated analysis
| Component | Directly analyze peak area (μ V.S) | Peak area (μ V.S) is analyzed in enrichment |
| Ethene (ethylene) | 4.040×10 5 | 4.053×10 7 |
| Ethane (ethane) | 1.158×10 6 | 1.166×10 8 |
| Acetylene (acetylene) | 2.061×10 5 | 2.086×10 7 |
| Propane (propane) | 1.348×10 6 | 1.295×10 8 |
| Isobutane (isobutene) | 6.588×10 5 | 6.603×10 7 |
| Normal butane (butane) | 1.365×10 6 | 1.314×10 8 |
In addition, in the experiment also to each component to be measured in dynamic Pre-concentration Method absorption/desorption efficient and the reproduction of analysis result measure, see Table 2 and 3 respectively.
The absorption of table 2 target component/desorption efficient
Table 3.2 Collection/recovery effciency for target complunds absorption/desorption efficient % component (compound) (collection/recovery efficency) ethene (ethylene) 99 ± 1 ethane (ethane) 101 ± 1 acetylene (acetylene) 102 ± 2 propane (propane) 96 ± 2 iso-butanes (isobutene) 100 ± 1 normal butanes (butane) 96 ± 1
The reappearance of table 3 analysis result
Table 3.3 The reproducibility of the analysis results
Component (compound) relative standard deviation (RSD) %
Ethene (ethylene) 13
Ethane (ethane) 1.2
Acetylene (acetylene) 2.9
Propane (propane) 2.1
Isobutane (isobutene) 0.7
Normal butane (butane) 0.7
Can find out by table 2 and 3: utilize dynamic Pre-concentration Method, the absorption of each component to be measured/desorption efficient＞94%, the reproduction error≤3%RSD of analysis result.
Therefore say that dynamic Pre-concentration Method has realized the enrichment efficiently, fast and accurately to the small size gaseous sample.
Adopt two kinds of different firing rates, a kind ofly in 6 times in second, column temperature is heated to 250 ℃, another kind is heated to 250 ℃ with column temperature in 25 times in second, it (is not enter analytical column behind the component desorption to be measured that desorption peaks to ethane is measured, detect but directly enter detecting device), see accompanying drawing 11,12, the resulting thermal desorption of kind of the situation of can seing before peak half-breadth only is 2～3 seconds, and the peak type is sharp-pointed and do not have and take off tail.A kind of desorption peaks of situation broad then then.
Claims (1)
1, a kind of dynamic pre-concentration device of gaseous sample, it is characterized in that: this device is by quantity tube (7), six-way injection valve (8), analytical column (9), four-way cutting valve (10) and evaporating column (11) are formed, one end of quantity tube (7) connects the inlet of analytical column (9) by six-way injection valve (8), the outlet of analytical column (9) is cut valve (10) by four-way and is linked to each other with detecting device (12), evaporating column (11) inlet joins by the other end of six-way injection valve (8) with quantity tube (7), sample introduction connects the two ends of quantity tube (7) by six-way injection valve (8), and carrier gas is cut valve (10) by four-way and linked to each other with evaporating column (11) with analytical column (9) respectively.
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|---|---|---|---|
| CN 00210483 CN2439025Y (en) | 2000-09-29 | 2000-09-29 | Dynamic pre-concentrating apparatus for gas sample |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00210483 CN2439025Y (en) | 2000-09-29 | 2000-09-29 | Dynamic pre-concentrating apparatus for gas sample |
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| CN2439025Y true CN2439025Y (en) | 2001-07-11 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100401060C (en) * | 2003-04-14 | 2008-07-09 | 珀金埃尔默Las公司 | Interface assembly for pre-concentrating analytes in chromatography |
| CN102498381A (en) * | 2009-07-31 | 2012-06-13 | 创控生技股份有限公司 | Gas collection and analysis system with front-end and back-end pre-concentrators and moisture removal |
| US9683974B2 (en) | 2009-07-07 | 2017-06-20 | Tricorntech Corporation | Cascaded gas chromatographs (CGCs) with individual temperature control and gas analysis systems using same |
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| US9921192B2 (en) | 2010-04-23 | 2018-03-20 | Tricorntech Corporation | Gas analyte spectrum sharpening and separation with multi-dimensional micro-GC for gas chromatography analysis |
| CN108107145A (en) * | 2017-12-12 | 2018-06-01 | 优泰科技（深圳）有限公司 | Gas concentration instrument |
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2000
- 2000-09-29 CN CN 00210483 patent/CN2439025Y/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100401060C (en) * | 2003-04-14 | 2008-07-09 | 珀金埃尔默Las公司 | Interface assembly for pre-concentrating analytes in chromatography |
| US9683974B2 (en) | 2009-07-07 | 2017-06-20 | Tricorntech Corporation | Cascaded gas chromatographs (CGCs) with individual temperature control and gas analysis systems using same |
| CN102498381A (en) * | 2009-07-31 | 2012-06-13 | 创控生技股份有限公司 | Gas collection and analysis system with front-end and back-end pre-concentrators and moisture removal |
| CN102498381B (en) * | 2009-07-31 | 2014-05-07 | 创控生技股份有限公司 | Gas collection and analysis system with front-end and back-end pre-concentrators and moisture removal |
| US9658196B2 (en) | 2009-07-31 | 2017-05-23 | Tricorntech Corporation | Gas collection and analysis system with front-end and back-end pre-concentrators and moisture removal |
| US9921192B2 (en) | 2010-04-23 | 2018-03-20 | Tricorntech Corporation | Gas analyte spectrum sharpening and separation with multi-dimensional micro-GC for gas chromatography analysis |
| US11035834B2 (en) | 2010-04-23 | 2021-06-15 | TricornTech Taiwan | Gas analyte spectrum sharpening and separation with multi-dimensional micro-GC for gas chromatography analysis |
| US11796515B2 (en) | 2010-04-23 | 2023-10-24 | Tricorntech Corporation | Gas analyte spectrum sharpening and separation with multi-dimensional micro-GC for gas chromatography analysis |
| CN107110832A (en) * | 2014-12-05 | 2017-08-29 | 斯特拉斯堡大学 | The detection method of at least one VOC contained by the detection microdevice and gaseous sample of VOC |
| US10823711B2 (en) | 2014-12-05 | 2020-11-03 | Universite De Strasbourg | Micro-device for detecting volatile organic compounds, and method for detecting at least one volatile organic compound contained in a gas sample |
| CN108107145A (en) * | 2017-12-12 | 2018-06-01 | 优泰科技（深圳）有限公司 | Gas concentration instrument |
| CN108387668A (en) * | 2018-05-04 | 2018-08-10 | 清华大学 | A kind of particulate organic matter on-line preconcentration resolver and its application method |
| CN108387668B (en) * | 2018-05-04 | 2023-04-11 | 清华大学 | Particle organic matter online enrichment and analysis device and use method thereof |
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