FIELD OF INVENTION
The subject matter of the present invention relates to a dynamic system for sampling volatiles from multiple specimens and method for sampling volatiles from multiple specimens.
BACKGROUND
Systems are designed to collect volatile from living things, organic matter, liquids, soil, atmospheric air etc. The volatile collection systems find its use in entomology to capture allelochemicals involved in tritrophic interactions to study insect pheromones and its dynamics, horticulture- to capture flower and fruits scents, to study flowers and fruits emission dynamics, plant physiology for studying plant metabolism under different gaseous and moisture regimes, and environmental monitoring.
China Pat. no. 203183881 discloses a plant volatile collecting system comprises a gas circular generating device, an active carbon filter, a humidifier, a seal sampling device and an absorbing column, wherein the gas circular generating device is provided with a first gas outlet and a first gas inlet, the first gas outlet, the active carbon filter, the humidifier, the seal sampling device, the absorbing column and the first gas inlet are sequentially connected through a ventilating pipe in a gas sealing manner. The drawback of this system is they can collect volatiles from a single subject specimen. These systems have a device, in which the subject specimen is placed to obtain the volatiles and they are very costly.
China Pat. no. 203741300U discloses an aromatic plant volatile collecting system which includes a collection box, a cultivation device and an adsorption device, wherein the collection box is provided with a gas inlet, a gas outlet, a water inlet and a water outlet. The cultivation device is positioned in the collection box; the cultivation device comprises a drop irrigation device which is provided with a water pipe. This system is complex and very costly as compared to the subject matter of present invention and also unable to collect volatiles from multiple specimen at a time.
In the journal of chemical ecology, vol. 20, page 593-607 discloses a system for the collection of volatiles produced by plants that minimizes stress on the plant in an environment that is free from chemical impurities. The entire system consists a guillotine chambers one of its main parts. The guillotine chambers is used to selectively exclude a part of specimen for the volatile collection which is very costly. 2
Further in the plant journal (2006) 45, page 540-560 a static and dynamic techniques are disclosed for the headspace collection of volatiles. Volatile collection system that have multiple chambers are also known. These systems collect volatiles from different subject specimens. However, these known systems are not multiunit systems in clusters but single unit systems in clusters. These systems are complex and costly as they uses separate flow meters for each chamber. Further, the volatile collection equipment can collect volatiles only from two subject specimens simultaneously and cannot collect volatiles from multiple subject specimen at a time.
In few volatile collection devices humidity is provided through an external bubbler and the humidity content is regulated by mixing it with dry air. In these systems each chamber need to be provided with separate bubblers and flowmeters to regulate the wet and dry air separately which again add complexity and cost to the system. Here the humidity (RH) control is not based on real time measurement but on the assumption that mixing dry air and wet air at a particular proportion maintains humidity at that proportion aeration unit can also act as a bubbler while bell jars are kept dry and the humidity to the system is provided from the aeration unit. In these volatile collection devices humidity cannot be regulated, which is undesirable. OBJECTS OF THE INVENTION
To overcome these shortcomings a dynamic system for sampling volatiles from multiple specimen and method for sampling volatiles from multiple specimens using the dynamic system is disclosed in the following paragraphs. In dynamic systems, some of the problems such as increases in temperature and humidity or accumulation of deleterious volatiles in the air surrounding the specimen are eliminated by a constant air stream. Dynamic headspace sampling represents the most frequently used technique in all areas of volatile analysis involving live specimen. In this sampling technique, a continuous air stream flows through the specimen chamber as a carrier gas, as a result volatiles collected in the trap are concentrated which results in improved sensitivity. Accordingly the objects of the present subject matter are as follows
The object of the present subject matter is to provide a dynamic system for sampling volatiles from
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multiple specimen at a time using a single flow meter and pump. Another object of the present subject matter is to provide a method for sampling volatiles from multiple specimen at a time using a single flow meter and pump.
Another object of the present subject matter is to provide a dynamic system for sampling volatiles from multiple specimen at a time that is simple and cost-effective.
Another object of the present subject matter is to provide a dynamic system for sampling volatiles from multiple specimen in 'pull' as well as 'push-pull' mode that is simple and cost effective. Yet another object of the present subject matter is to provide a method for sampling volatiles from multiple specimen that is simple and cost-effective. SUMMARY
Accordingly, the present subject matter relates to a dynamic system for sampling volatiles from multiple specimen and the present subject matter relates to a method for sampling volatiles from multiple specimens using the dynamic system.
In accordance with an aspect of the disclosure there is provided a system for sampling volatiles from multiple specimens. The system comprising an aeration unit having at least one air inlet and plurality of outlet ports; plurality of chambers, each chamber being provided with a stopper, the chamber being in a fluid communication with one of said plurality of outlet ports of said aeration unit via a tube; a vacuum unit having at least one inlet port in a fluid communication with said chamber via a tube; and a suction unit in a fluid communication with outlet of said vacuum unit via a single flow meter.
According to another aspect of the disclosure there is provided a method for sampling volatiles from multiple specimens using the dynamic system, the method comprising placing a specimen in atleast one chamber; obtaining purified air from an aeration unit; passing the purified air from one of the outlet port of the aeration unit in to the chamber via tube connected between the one of the outlet ports of the aeration unit and the chamber to pass on to the specimen kept in chamber to obtain air containing volatiles; guiding the air containing volatiles from one of the chambers to a volatile collection trap by a suction unit via a single flow meter; passing the air after trapping volatiles in the volatile collection trap through the tube connected between one of a inlet port of the vacuum unit and the stopper of the chamber by a suction unit via a single flow meter during the passage of the air containing volatiles; 4
extracting the volatiles trapped in the tube during the passage of air containing volatiles.
In an embodiment of the present disclosure, the aeration unit is provided with an adsorbent matrix.
In another embodiment of the present disclosure aeration unit has two flow meters, two Y-connectors and an air source.
In another embodiment of the present disclosure, the chamber is a bell jar with an open bottom.
In another embodiment of the present disclosure, the chamber is made air tight by placing a gasket or by immersing in water kept in a flat bottomed plate or both.
In yet another embodiment of the present disclosure chamber is ventilated at the bottom by keeping on a lid with a hole at the middle, closing a bucket.
In yet another embodiment of the present disclosure, the stopper is fitted with L-bend tubes.
In yet another embodiment of the present disclosure, the stopper is fitted with a sleeve
Further in an embodiment of the present disclosure, the sleeve fitted in said stopper is provided with a volatile collection trap.
In another embodiment of the present disclosure, the suction unit is a pump. BRIEF DESCRIPTION OF DRAWINGS
The above and other features, aspects, and advantages of the present subject matter will be better understood with regard to the following description, and accompanying drawings. The figures show:
Figure 1 shows a schematic view of a system (100) for sampling volatiles from multiple specimen s according to an embodiment of the present subject matter.
Figure 2a and 2b show schematic views of different embodiments of an aeration unit (2) used in the dynamic system (100) under pull and push pull respectively according to an embodiment of the present subject matter.
Figure 3a and 3b shows a schematic view of an arrangement to provide humidity as providing air through an external source and pumping of atmospheric air respectively according to another embodiment of the present subject matter.
Figure 4 shows a stopper (19) plugging the bell jar or specimen chamber (3) which hold tubes to
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receive filtered air in the specimen chamber (3), to trap volatiles and to remove break through air after volatile collection according to an embodiment of the present subject matter.
Figure 5a and 5b show schematic view of an arrangement of open type specimen chamber for collecting volatiles from potted plants by push-pull system according to an embodiment of the present subject matter.
DETAILED DESCRIPTION WITH REFERENCE TO ACCOMPANYING DRAWING
Figure 1 shows a schematic perspective view of a 'pull' mode dynamic system for sampling volatiles from multiple specimens. In pull type dynamic system, air is pulled over the specimen. The dynamic system 100 has a support 1, an aeration unit 2, a specimen chamber 3, a vacuum unit 4, a flow meter 5 and a suction pump 6. The aeration unit 2 is provided on the upper part of the support 1. The aeration unit 2, the vacuum unit 4 and the specimen chamber 3 are in fluid communication. According to an embodiment of the present subject matter, the aeration unit 2 has a wire mesh air inlet 7 and multiple ports 8. The air inlet 7 is provided to intake atmospheric air. The multiple ports 8 that are provided on the aeration unit 2 are connected to the individual specimen chamber 3 respectively via tubes 15. The specimen chamber 3 is a bell jar. The aeration unit 2 has adsorbent 9 at the bottom contained with a fine wire mesh; its mesh size depends upon the particle size of the adsorbent matrix used. The atmospheric air is sucked through the wire mesh inlet 7 and gets purified by adsorbent 9 as shown in fig.1. The adsorbent 9 can be of any type but in this system an activated charcoal and or silica is used.
The 'pull' mode dynamic system as in fig 1 uses atmospheric air without any additional humidity source, which is suitable to be used in a controlled environment chamber such as glass house. In pull mode dynamic system, air is pulled over the specimen through the pump 6. To make the system air proof, bell jar 3 is to be kept on a silicon gasket 18, which in turn is kept on a steel plate. Humidity can also be provided by keeping water in the plate over which the bell jar 3 is kept, which will make the system air proof with or without a silicon gasket 18 as shown in fig.1. In such situations the humidity cannot be regulated while the system 100 is in operation. 6
According to another preferred embodiment of the present subject matter, in ‘push-pull’ mode dynamic system, the aeration unit 2 has an aeration tube adsorbent 9 is tied around its perforated glass bulb using a muslin cloth and the atmospheric pressure is pumped to the adsorbent 9 to purify it as in fig.2(b).
Figure 3(a) shows a schematic view of an arrangement to provide air through an external air source 11 according to yet another preferred embodiment of the present subject matter in 'push-pull' mode dynamic system. Air source 11 is either compressed artificial air or any desired mixture of gas, for example air with elevated CO2 is pumped into the aeration unit 2. When atmospheric air is pumped, the adsorbent 9 for air purification can also be provided as in fig. 3(b).
The desired humidity can be maintained in the 'push-pull' mode dynamic system by connecting the aeration unit 2 to a humidifier 12 and an external air source 11 as in fig. 3(a) or atmospheric air as in fig. 3(b) via a Y-connector 13 (a). In order to have desired relative humidity, both arms of the Y-connector 13(b) have to be differentially regulated using separate flow meters 5(a) and 5(b). A humidity sensor, which is preferably a hand held humidity sensor 14, can be placed inside the aeration unit 2. The air source 11 as in fig. 3(a) or atmospheric air as in fig. 3(b) can supply air to the aeration unit 2 and humidifier 12 via the Y-connector 13(a). Here, a single humidity source and the air source can be used for all specimen chambers 3 of the volatile collection system 100.
In 'pull' mode as well as 'push-pull' mode of volatile collection, each of the specimen chamber or bell jar 3 is connected to the aeration unit 2 and vacuum unit 4 via tubes 15 and 16 fitted with adaptors 17 at the ends, preferably made of glass.
The specimen from which the volatiles are to be collected is placed in each of the bell jar 3.The specimen can be of any type like plants, animal and inert matters etc. The tubes 15 and 16 connect the bell jar 3 to the outlet of aeration unit 2 and inlet 4a of the vacuum unit 4 respectively. Each of the bell jar 3 comprises a stopper 19 that is provided to plug the mouth of the bell jar 3. The stopper 19, preferably of Teflon has an inlet tube 20 and outlet tube 21, which are preferably L-bend tubes. The long tube 20 from each of the bell jar 3, which is connected to the outlet 8 of aeration unit 2 via tube 15, guides the purified air from the aeration unit 2 to the bell jar 3. The short tube 21 from each of the bell jar 3, which is connected to the inlet 4a of the vacuum unit 4 via tube 16, guides the air out from the bell jar 3 to the vacuum unit 4. Further, the stopper 19 is provided with a sleeve 22, which is 7
preferably of Teflon, receives the air outlet tube 21 at its top end and the volatile collection trap 23 at its bottom end. The other end of the air outlet tube 21 is connected to inlet 4a of the vacuum unit 4 via tube 16 which vacuums the break through air from volatile trap. The tube 16 which connects tube 21 is of less costly material, where we used silicon, which can emit some volatiles, but won’t interfere with the volatiles adsorbed in the trap as it is fitted at the trap exit.
The air inlet tube 20 is placed closed to the specimen so that it leaves purified air over and amidst the specimen. The volatile collection trap 23 is placed in the sleeve 22 of the stopper 19 in a vertical position so that volatile charged air above the specimen passes through entire length of the volatile collection trap 23, thus also suitable for loosely packed traps, where voids may be created in continuous air-flow when fitted horizontally.
The outlet 4b of the vacuum unit 4 is connected to the pump 6 via a flow meter 5(c). The pump 6 has regulator which helps in regulating the air flow, which can be precisely monitored by the flow meter 5 (c). An inflow of air is created in the aeration unit 2 when pump 6 starts pumping the air out of the vacuum unit 4. The air entered gets purified through the adsorbent 9 and distributed in to the specimen chambers 3. The air exit out of the specimen chamber 3 is laden with volatiles which are adsorbed into the adsorbent material packed in the volatile collection trap 23. The air pulled out or break through air of the volatile collection trap 23 is cumulatively removed by the vacuum unit 4 and finally through the air out let 24 of the pump as shown in fig.1.
Thus the present system 100 enables the collection of volatiles from many vacuum units at a time using single flow meter and single pump in ‘pull’ mode and two flow meters and two pumps in ‘push- pull’ mode.
Figure 5a and 5b show an arrangement of ‘open type’ specimen chamber 3 where a portion of the subject specimen is excluded according to another embodiment of the present subject matter, which is an alternative to the guillotine system of collecting volatiles from the potted plant in ‘push- pull’ mode. The part of specimen to be excluded here is a pot 25 and the soil within it which can interfere with the collection of plant volatiles. The pot 25 is kept in a bucket 26 in such a manner that the plant canopy rises well above the rim of the bucket. The bucket has a lid 27 in which a hole is provided so that the plant canopy can be brought comfortably above the hole. A skirting is provided around the stem of the 8
plant starting below the lid level, rising up to cover the lid of the bucket. The skirting provided is preferably of aluminium foil. Once this arrangement is over, the bell jar 3 is kept covering the plant canopy over the lid of the bucket, thus excludes the potted portion below.
Further the volatiles trapped in the volatiile collection trap (23) are extracted by various known methods and then analyzed by the various standard techniques known in the art such as gas chromotography.
EXAMPLE
An example of ‘push-pull’ collection of volatile from a potted plant is given below. Air is pushed into system using a pump and flow meter through the aeration chamber as in 2 (b) and 3(b) or compressed air as in 3 (a). The purified air goes into the specimen chamber 3 as in fig.1. A portion of the air is pulled out of the specimen chamber 3 through the volatile trap 23 using pump 6 and flow meter 5 (c) as in fig.1 and remaining airflow escapes through the vent at aluminium foil skirting around the canopy as in 5 (b). Buy pulling out less than the air (75-80%) pumped into the specimen chamber 3, it is ensured that some air will always flush down through the vent in the bucket lid and no air from the excluded portion would enter the system. Further the volatiles trapped in the volatile collection trap (23) are extracted by various known methods and then analyzed by the various standard techniques known in the art such as gas chromotography.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the disclosure should not be limited to the description of the preferred embodiment contained therein.

We Claim:
1. A dynamic system (100) for sampling volatiles from multiple specimens comprising
an aeration unit (2) having at least one air inlet (7) and plurality of outlet ports (8) ;
plurality of specimen chambers (3), each specimen chamber (3) being provided with a stopper (19), the specimen chamber (3) being in a fluid communication with one of said plurality of outlet ports (8) of said aeration unit (2) via a tube (15);
a vacuum unit (4) having at least one inlet port (4a) in a fluid communication with said specimen chamber (3) via a tube (16); and
a suction unit (6) in a fluid communication with outlet (4b) of said vacuum unit (4) via a single flow meter (5c).
2. The dynamic system (100) as claimed in claim 1, wherein said aeration unit (2) comprises an adsorbent matrix.
3. The dynamic system (100) as claimed in claim 1, wherein said aeration unit (2) is provided with a humidifier (12), two flow meters (5a, 5b), two Y-connectors (13a, 13b) and an air source (11).
4. The dynamic system (100) as claimed in claim 1, wherein each of said specimen chamber (3) is a bell jar with an open bottom.
5. The dynamic system (100) as claimed in claim 4, wherein said specimen chamber (3) is made air tight by placing a gasket (18) or by immersing in water kept in a flat bottomed plate or both.
6. The dynamic system (100) as claimed in claim 4, wherein said specimen chamber (3) is ventilated at the bottom by keeping on a lid with a hole at the middle (27), closing a bucket (26).
7. The dynamic system (100) as claimed in claim 1, wherein the stopper (19) is fitted with L-bend tubes (20, 21). 10
8. The dynamic system (100) as claimed in claim 7, wherein the stopper (19) is fitted with a sleeve (22).
9. The dynamic system (100) as claimed in claim 8, wherein the sleeve (21) fitted in said stopper (19) is provided with a volatile collection trap (23).
10. The dynamic system (100) as claimed in claim 1, wherein the suction unit (6) is a suction pump.
11. A method for sampling volatiles from multiple specimens using the dynamic system (100) as claimed in claim 1 in ''push'' mode as well as ''push-pull mode'', the method comprising
placing the specimen in atleast one of the specimen chamber (3);
obtaining purified air from the aeration unit (2);
passing the purified air from one of the outlet port (8) of the aeration unit (2) in to the specimen chamber (3) via tube (15) connected between the one of the outlet ports (8) of the aeration unit (2) and stopper (19) of the specimen chamber (3) to pass on to the specimen kept in specimen chamber (3);
adsorbing the volatiles in a volatile collection trap (23) of stopper (19) while guiding the air containing volatiles from one of the specimen chambers (3) to the vacuum unit (4) by the suction unit (6) via single flow meter (5c);
passing the air after adsorbing volatiles in the volatile collection trap (23) through the tube (16) connected between one of the inlet port (4a) of the vacuum unit (4) and stopper (19) of the specimen chamber (3) by the suction unit (6) connected in the outlet port (4b) of the vacuum unit (4) via single flow meter (5c).
extracting the volatiles trapped in the volatile collection trap (23).