CN109883773A

CN109883773A - A kind of in situ plant root volatile organic matter collection and determination method

Info

Publication number: CN109883773A
Application number: CN201910206400.0A
Authority: CN
Inventors: 何禾
Original assignee: Hainan University
Current assignee: Hainan University
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2019-06-14

Abstract

The invention discloses a kind of root system of plant volatile organic matter collection in situ and measuring methods, this method can be under the premise of not destroying root system of plant, pass through the collection system of the components compositions such as homemade trapping bag, it realizes that in-situ acquisition is woody or the volatile organic matter of Herb Root release under natural conditions, then injects a sample into portable gas chromatograph-mass spectrometer and be successfully separated root system of plant BVOCs with the program after optimizing.Its key step are as follows: envelope plant in body root system end with trapping bag, afterwards by PDMS/DVB absorption needle insertion trapping bag thief hatch, then volatile organic matter is attached on absorption needle, is parsed through portable gas chromatograph-mass spectrometer (GC-MS) injection port high temperature, then carry out separation identification.The present invention because by the way of collecting in situ can release conditions under more acurrate reflection plant natural conditions, have the characteristics that true, convenient, easy to operate, meet the needs that field directly acquires plant source root system volatile organic matter.

Description

It is a kind of original position root system of plant volatile organic matter collect and measuring method

Technical field

Collected the invention belongs to environmental monitoring technology field more particularly to a kind of root system of plant volatile organic matter in situ and Measuring method.

Background technique

Plant source volatile organic matter (BVOCs), which refers to, passes through the positions such as blade, flower, fruit, root system outwardly by plant Release, the small molecule compound with the characteristics such as low boiling point is volatile.The volatility non-methane gas in the whole world annual 90% or more Discharge derives from plant, this substance not only influences in plant growth, breeding, defence or Atmospheric physical and chemical processes Key link more generates far-reaching effect to atmosphere quality, troposphere chemistry and Global Carbon nitrogen cycle etc..Study table Bright, BVOCs can attract pollinator and improve plant propagation ability, and plant can also be helped to resist the adverse circumstances such as high temperature, while its kind Class and content are also to measure the major criterion of aromatics plant quality.It is a to other that plant not only passes through release volatile organic matter Body transmits information, this substance more rises in plant and its pest and the interbiotic Interaction of third trophic level especially prominent Effect.Root system discharges BVOCs compared with aboveground vegetation part, equally has important ecological significance, it significantly affects plant Between kin recognition and interaction, ecological environment of soil is formed very important.But since its content is low, complicated component, and by The multifactor impacts such as vegetation type, rhizospheric environment and edaphon are difficult to efficiently separate identification always.Therefore, it collects and examines The ingredient of measuring plants volatile matter is that one of research hotspot in fields such as Phytochemistry, ecology, foundation are reliable accurate for a long time Measuring method is collected convenient for the root system volatile matter of operation, can help to understand in depth the object between foot end and soil environment Mass-energy amount and information transmitting.

Currently, the collection measuring method multiplicity of Herbivore organic matter, but it is most of for blade, flower, fruit and other places Upper part.In numerous methods, with what is combined using solid phase microextraction (SPME) and thermal desorption (TD) collection with gas chromatograph-mass spectrometer It is most widely used, the former collection process needs are removed detected part from plant, and the latter is often entire by plant It is colonized in special container and is sampled again.For root system of plant, these make plant be detached from parent or itself primitive environment Mode be unable to meet demand because time-consuming growth process complexity be easy to cause result inaccurate.The present invention is with root system of plant volatility Organic matter is object, trapping bag and absorption needle cooperation is sampled, and choose portable gas chromatograph-mass spectrometer in specific analysis method Under the conditions of analysis measurement is carried out to target compound, be conducive to more acurrate convenient acquisition measurement root system release volatile matter.

Summary of the invention

The object of the present invention is to provide a kind of root system of plant volatile organic matter collection in situ and measuring methods, accurately to obtain Take and detect plant under natural growth conditions root system release volatile organic matter type and quantity, have it is easy, sensitive, The features such as pollution is few is suitble to sampling and analysis under natural conditions to root system of plant volatile matter.

In order to achieve the above purpose, the present invention the following technical schemes are provided:

It is a kind of original position root system of plant volatile organic matter collect and measuring method, by special designing trapping bag composition The system volatile organic matter that herborization root system discharges at normal temperature, then use portable gas chromatography and mass spectrometer GC-MS carries out separation determination to target compound, when collecting sample, without removing root system from plant, need to only use trapping Bag envelopes root system of plant end, after by with higher sensitivity PDMS/DVB absorption needle insertion bag, then volatile organic matter It is attached on absorption needle, is parsed by gas chromatograph-mass spectrometer injection port high temperature, target compound enters instrument with carrier gas and separated Identification.

The root system of plant volatile organic matter in situ is collected and measuring method, the specific steps are as follows:

(1) selection fair weather carries out sample acquisition, for xylophyta, the complete lateral root of its health should be taken to dig out, and Herbaceous plant then integrally digs out ball, carefully shakes off the surface dust on root system to be measured, is placed on appropriately sized clean trapping bag In, it covers in exposed root system end, and tightened sack with flexible silicon cushion rubber, and smear appropriate vaseline at gap to guarantee bag Interior opposing seal；

(2) bag air inlet/outlet will be trapped with the PTFE hose of internal diameter 6-10mm to connect with atmosphere sampling instrument respectively, and into Air filter is accessed between the atmosphere sampling instrument and air inlet at mouth end；

(3) after there is air in discharge trapping bag Central Plains, absorption needle is inserted into purified trapping bag acquisition port, releases aging Fiber head stablize absorption 30-60min, retract fiber head, then extract absorption needle out, be put into ice chest to save and take back laboratory and wait for It surveys；

(4) the absorption needle after sampling is rapidly inserted into GC-MS injection port, releases fiber header parsing 0.5-3min, passes through the instrument Device collects target compound mass spectrogram and carries out qualitative and quantitative analysis.

Different types of individual plants are directed in the step 1, the selection for sampling root system is different, and herbaceous plant will entirely be planted Strain ball, which is dug out, to be placed in trapping bag；Xylophyta then selects the lateral root system easily dug out to be put into trapping bag.

The trapping bag is designed for plant root growth characteristic, by the perfluoroethylene third of thickness 0.07-0.10mm Alkene film (fep film) is made, sealed around, there is 2 polytetrafluoroethylene (PTFE) (PTFE) breather valves on this bag of bag, and one is upper end installation Through-type breather valve is used as air inlet, communicates with atmosphere, another two pasted valve type is located at the bag side different with through-type valve position Below face, this valve one end is as trapping bag gas outlet, and the other end is as acquisition port, the interior removable lining sealed silicon rubber mat of tool, side Just absorption needle insertion.

Air filter in the step 2 is made of the glass tube of two Φ 6cm × 28cm, is respectively charged into pipe suitable Carbon content active and MnO₂, respectively there is the threaded cylindric ventilation nozzle of an outer diameter 7-11mm before and after glass tube, internal diameter 6-10mm's The connection of PTFE hose accesses this device in entire sampling system.

Bag purification process is trapped in the step 3 are as follows: open the volatile matter collection system being completed, make air inlet/outlet two End gas sampling apparatus simultaneously keep 0.5L/min be evacuated 15-30min, but sampling needle and be not inserted into trapping bag in, thus by bag Residual air discharge.

The fiber head that needle is adsorbed in the step 3 is 65-110 μm of PDMS/DVB material, is installed in absorption needle, and Freely it can be released or be withdrawn by the flexible of needle rear handle, it need to be in makings injection port with 250-270 DEG C before first time use Aging 0.5-1h, and used also remove in injection port vaporizing chamber with 220 DEG C of heating 5-10s every time and remain.

During adsorbing needle sampler in the step 3, atmosphere sampling instrument sucking rate is 0.2-0.5L/min, and air inlet/outlet Sucking rate keeps balance, acquires 30-60min, acquires gas 6-30L altogether.

Wherein atmosphere sampling instrument is binary channel atmosphere sampling instrument, range of flow 0.1-1.2L/min, timing range 1- 99min, operating temperature -10~40 DEG C.

For being lined with one piece of silicagel pad inside the breather valve of absorption needle insertion in the step 3, regularly replace closed to guarantee Property.

GC-MS analysis method in the step 4 the following steps are included:

(1) chromatographic condition: chromatographic column is DB-624 (5m × 0.1mm × 0.56 μm) gas chromatographic column；Injector temperature 220 ℃；Injection port does not shunt or split ratio 5:1；Flow rate of carrier gas 1mL/min；Temperature program is 40 DEG C of initial temperature, keeps 0.5min, 160 DEG C are risen to 10 DEG C/min, 0.5min is kept, finally rises to 220 DEG C with 20 DEG C/min；

(2) Mass Spectrometry Conditions: EI full scan mode, ion strap mass analyzer, scanning range 50-550amu；

(3) qualitative-and-quantitative method: initial characterization is carried out using substance of the standard spectrum library to detection, then is referred to István Kovács reservation Number (Kovats ' Retention Index) auxiliary is qualitative, and it is quantitative that peak area normalization method, external standard or internal standard method are used as substance Method.

The invention has the advantages that

1, compared with traditional technology, have the advantage that traditional BVOCs collection mode is mainly divided to two classes, solid phase microextraction With thermal desorption method.The former needs first to pick plant detected part (leaf, flower, fruit etc.), then carries out later collection, it is clear that wins The wound of generation can promote plant to discharge more metabolins, bring errors of analytical results.Latter method usually moves plant It plants in special container, is detached from primitive environment, cause result inaccurate, and the thermal desorption pipe that collection uses is expensive, have certain Service life, lead to cost increase.In contrast, the trapping sampling device production letter that sampling process of the present invention uses Single, cost performance is high, and volatile matter sample can be collected in situ under conditions of not destroying plant root, and entire collection step is not complicated, Target compound is responded sensitiveer.In addition, portable gas chromatograph-mass spectrometer In-situ test is used in this method, without such as tradition side Method transports sample back laboratory, can substantially reduce the loss and pollution of transportational process sample.Therefore, this method can more acurrate reflection The release conditions of root system volatile organic matter under plant natural conditions, have the characteristics that true, convenient, easy to operate, meet field Directly acquire the needs of plant source root system volatile organic matter.

2, the trapping bag that the present invention designs ensures that the abundant collection of target compound is not got dirty in terms of material and structure two Dye.FEP, which traps bag and its PTFE air valve, has excellent chemistry and thermal stability, and it is dry that impurity will not have both been generated in sampling process It disturbs, and can guarantee the air-tightness of entire sampling system.Target substance can be sufficiently collected to be further ensured that this traps packed set, It respectively designs a blow vent up and down, and the two is located at a bag both ends, and gas outlet and adsorption orifice are integrated in a two-way valve Men Shang, the pure air and be wrapped by after the volatile organic matter that root system is discharged is sufficiently mixed again that this design ensures to suck in bag Successively pass through adsorption orifice and gas outlet, guarantees to be then exhausted from after mixture is first adsorbed by sampling needle.Meanwhile using soft easily plasticity Coating of the bag as root system of plant is trapped, more suitable for the diversity Root morphology of different type plant.

3, the present invention carries out target substance using the bipolarity fiber head of two kinds of mixed materials of 65-110 μm of PDMS/DVB Absorption expands adsorption range and sensitivity to sample, it is ensured that sample absorption is complete, and the fiber head can pass through activating and regenerating weight It is multiple to use, economical and efficient.

4, MnO is added in volatile matter trapping system in the present invention₂With active carbon screen pipe, can exclude moisture in air with it is smelly Oxygen interference.Portable gas chromatograph-mass spectrometer involved in method simultaneously is equipped with optimized chromatographic column and analysis method, on the one hand increases By force to the separating capacity at target compound peak, chromatography peak stretching is avoided, it is ensured that compound characterization is quantitative accurate, in addition can accelerate point Analyse efficiency and the sensitivity to compound.

Detailed description of the invention

Fig. 1 show present invention trapping bag schematic diagram, wherein 1 is air inlet, 2 be sample acquisition port, and 3 be gas outlet, and 4 are Perfluoroethylene-propylene film.

Fig. 2 show collection system schematic diagram of the present invention, wherein 1,10 be air sampling pump, 2 be filter device, and 3 are MnO₂Particle, 4 be active carbon particle, and 5 be PTFE hose, and 6 be trapping bag, and 7 be root system, and 8 be sampling needle, and 9 be adsorption head, arrow Indicate gas flow direction.

Fig. 3 is shown in embodiment 1 to the total ion analyzed after the collection of xylophyta root system volatile organic matter with GC-MS Flow graph.

Fig. 4 show trapping bag in embodiment 1 and does not wrap up plant root, i.e. the GC-MS total ion current figure of blank sampling.

Fig. 5 is shown in embodiment 2 to the total ion analyzed after the collection of Herb Root volatile organic matter with GC-MS Flow graph.

Specific embodiment

Below in conjunction with specific example, technical scheme is described further:

Embodiment 1

Tree root system volatile organic matter is adsorbed with root system of plant volatile organic matter collection system in situ, then with portable Formula gas chromatograph-mass spectrometer carries out qualitative and quantitative analysis to target compound.

Sampling process: selection fair weather completely digs out its lateral root using healthy arbor as object, carefully shakes off thereon Surface dust is placed in clean trapping bag (such as Fig. 1), sack flexible silicon cushion rubber banding, and smears appropriate vaseline at gap. Then atmosphere sampling instrument (Jiangsu Ke Yuan Electronic Instruments Plant, KDY-B) and air filter are sequentially ingressed into trapping with PTFE tube Bag air inlet.To keep gas balance in bag, another atmosphere sampling instrument is connect (such as Fig. 2) with its gas outlet.Remove sampling In system pipeline and bag after impurity, activated absorption needle (Suplco, the U.S.) is inserted into trapping bag, pumping sampling.Flow 0.5L/min, 30min acquire 15L gas altogether, are sufficiently adhering to target compound in the extracting head of absorption needle.

Materials analysis methods: sampling needle is inserted into gas chromatograph-mass spectrometer (Mars 400plus) injection port, while starting chromatography Analysis.Chromatographic condition are as follows: chromatographic column is DB-624 (5m × 0.1mm × 0.56 μm) gas chromatographic column；220 DEG C of injector temperature； Injection port does not shunt or split ratio 5:1；Flow rate of carrier gas 1mL/min；Temperature program is 40 DEG C of initial temperature, keeps 0.5min, with 10 DEG C/min rises to 160 DEG C, keeps 0.5min, finally rises to 220 DEG C with 20 DEG C/min.Mass spectrum is EI full scan mode, Ion strap mass analyzer, scanning range 50-550amu.Using standard spectrum library lookup, Kovàts retention index (Kovats ' Retention Index) it calculates and is compared with standard items qualitative.Substance is quantified with peak area normalization method.

By above-mentioned collection and qualitative-and-quantitative method, the volatile organic matter total ion current figure of Tree root system release is as schemed Shown in 3.

For collection system performance is described, will trapping bag carry out blank sampling, and according to the above method to substance into Row analysis, the total ion current figure of sample are as shown in Figure 4, it is seen that do not have target substance appearance in blank sample.As shown in Table 1, with Other methods compare, and no matter from the target substance type or substance responds degree analyzed, this collection system and analysis method are equal With some superiority.

Table 1 compares the difference that distinct methods collect root system volatile constituent

ND: expression is not detected.

Embodiment 2

Process and Qiao with root system of plant volatile organic matter collection system in situ absorption draft root system volatile organic matter The method that wood is collected is slightly different.When acquiring sample, whole root systems are dug out as far as possible, carefully shrug off surface dust, then trapped with cleaning Bag encases entire ball, mouth flexible silicon cushion rubber banding, and appropriate vaseline is smeared at gap.Subsequent process and embodiment 1 It is similar.Then qualitative and quantitative analysis is carried out to target compound with gas chromatograph-mass spectrometer.The total ion current figure of this kind of root system volatile matter As shown in Figure 5.

Claims

1. a kind of in-situ plant root volatile organic matter collection and assay method, it is characterized in that, collect the volatile organic matter that plant root system discharges under normal temperature by the system that the collection bag of special design is formed, use portable gas chromatography and mass spectrometry again. The target compounds are separated and determined by GC-MS. When collecting samples, there is no need to remove the root system from the plant, just cover the end of the plant root system with a collection bag, and then attach the highly sensitive PDMS/DVB adsorption needle. Insert the bag into the bag, and then the volatile organic compounds are attached to the adsorption needle. After high-temperature analysis at the injection port of the GC-MS, the target compounds enter the instrument with the carrier gas for separation and identification.

2. in-situ plant root volatile organic matter collection and assay method according to claim 1, is characterized in that, concrete steps are as follows:

(1) Carefully dig out the root system of the plant to be tested, shake off the soil attached to the root system, select a suitable size collection bag to cover the end of the exposed root system, and fasten the bag mouth with an elastic silicone ring, and apply an appropriate amount of Vaseline to the gap to ensure The inside of the bag is relatively sealed;

(2) Use a PTFE hose with an inner diameter of 6-10mm to connect the air inlet and outlet of the capture bag to the air sampler respectively, and connect the air filter device between the air sampler at the inlet end and the air inlet;

(3) Insert the adsorption needle into the collection port of the purified collection bag, push out the aged fiber head for stable adsorption for 30-60 minutes, retract the fiber head, then pull out the adsorption needle, put it in the ice box, save it and bring it back to the laboratory for testing;

(4) After sampling, the adsorption needle is quickly inserted into the GC-MS injection port, the fiber head is pushed out for 0.5-3 minutes, and the mass spectrum of the target compound is collected by the instrument for qualitative and quantitative analysis.

3. in-situ plant root system volatile organic matter collection and assay method according to claim 1, is characterized in that, in described step 1, for different types of plant individuals, the selection of sampling root system is different, and herbal plants will whole plant root. The balls are dug out and placed in the collection bag; the woody plants choose the lateral roots that are easy to dig out and put in the collection bag.

4. The in-situ plant root volatile organic matter collection and assay method according to claim 1, wherein the collection bag is designed for plant root growth characteristics, and is made of polyperfluoroethylene propylene with a thickness of 0.07-0.10mm. The bag is made of film. There are 2 PTFE vent valves on the bag, one of which is a straight-through vent valve installed on the upper end as an air inlet, and the other is a two-way vent valve installed on the bottom of the side of the bag. Gas port and collection port.

5. in-situ plant root volatile organic matter collection and measuring method according to claim 1, is characterized in that, the air filter device in described step 2 is made up of two glass tubes of Φ 6cm × 28cm, and the tube is filled with respectively Appropriate amount of activated carbon and MnO ₂ .

6. in-situ plant root volatile organic matter collection and assay method according to claim 1, is characterized in that, in described step 3, the purifying process of the collection bag is: open the volatile matter collection system that the assembly is completed, make the air inlet and outlet two. The end gas sampler was kept at 0.5 L/min for 15-30min to exhaust the residual air in the bag.

7. The in-situ plant root volatile organic matter collection and assay method according to claim 1, wherein the fiber head of the adsorption needle in the step 3 is 65-110 μm PDMS/DVB, and needs to be in The gas injection port is aged at 250-270℃ for 0.5-1h, and after each use, it needs to be heated at 220℃ for 5-10s in the vaporization chamber of the injection port to remove residues.

8. The method for collecting and measuring in-situ plant root volatile organic compounds according to claim 1, wherein in the step 3, in the sampling process of the adsorption needle, the air extraction volume of the air sampler is 0.2-0.5L/min, and The suction volume of the air inlet and outlet is kept in balance, and the collection is 30-60min, with a total of 6-30L of gas collected.

9. in-situ plant root volatile organic matter collection and measuring method according to claim 1, is characterized in that, in the described step 3, the ventilation valve that the adsorption needle is inserted into is lined with a piece of silica gel pad, which is regularly replaced to ensure airtightness .

10. in-situ plant root volatile organic matter collection and assay method according to claim 1, is characterized in that, in described step 4, GC-MS analysis method comprises the following steps:

(1) Chromatographic conditions: the chromatographic column is a DB-624 (5m×0.1mm×0.56μm) gas chromatographic column; the inlet temperature is 220°C; the inlet splitless or split ratio is 5:1; the carrier gas flow rate is 1mL/min ; The heating program is the initial temperature of 40°C, hold for 0.5min, rise to 160°C at 10°C/min, hold for 0.5min, and finally rise to 220°C at 20°C/min;

(2) Mass spectrometry conditions: EI full scan mode, ion trap mass analyzer, scanning range 50-550amu;

(3) Qualitative and quantitative methods: use the standard spectral library to initially qualify the detected substances, and then use the Kovatz retention index to assist in the qualitative determination.