DE102009018021A1 - Microdosing system with a pulsed laser - Google Patents

Abstract

Known microdosing systems for use in various technical fields (printing technology, EUV production, measurement technology, chemical / biotechnological analysis) produce discrete quantities of fluid down to the femtogram range by means of micropumps, ultrasonic exciters, electromagnetic valves or displacement membranes. Alternatively, in the microdosing system according to the invention, minimal gas clouds are generated with discrete quantities down to the pico- and femtogram area with a defined frequency and pulse duration by means of a pulsed laser (11). For this purpose, a riser capillary (07) which is self-filling with fluid (06) is provided which projects into a flow channel (05) with a nozzle opening (09). The focus (13) of the pulsed laser (11) is directed to the nozzle opening (09) or to the riser capillary (07). The emitted laser pulses (12) have a variable energy greater than the evaporation energy of the fluid (06), so that at each laser pulse (12) a gas cloud (02) in the flow channel (05) (depending on the laser focus (13) either by direct evaporation or by pressure pulse) is initiated. Laminar layered air preferably flows in the flow channel (05). In order to prevent smearing of the gas clouds (02), their concentration in the low-pressure regions (23) of an ultrasonic wave (22) may be provided.

Description

The The invention relates to a microdosing system for non-contact Introduction of Discrete Fluid Quantities from a Fluid Reservoir in a walled and traversed by a carrier gas Flow channel via a dosing with a front-side metering opening by means of a generator unit for generating the discrete quantities of fluid, wherein the dosing line and the generator unit outside the flow channel are arranged.

When Microdosing system is called a device with the microscopic small discrete quantities of fluid in a volume range of below one Milliliters, preferably below one microliter into the femtoliter range, are ejectable. To distinguish is the touching Dosage in which the amount of fluid through contact with a substrate is withdrawn, and the non-contact dosage, at the amount of fluid is released freely into the room. The non-contact Dosage has opposite to the touching dosage the big advantage that no contact with the substrate and therefore no elaborate adjustment measures simultaneous risk of substrate damage made must become. Therefore, the contactless dosing is the subject various developments. The progressive miniaturization in almost all technical areas represents industry, development laboratories and Research institutions face ever new challenges. always smaller amounts of adhesives, oils, inks and one A large number of other media must be precise in the shortest amount of time Cycle times are dosed process reliable. There are besides the Aspect of a precise dosage especially the aspect a precise dose, which is used for analytical tests, for example, in the fields of pharmacy and biotechnology, is required. Overall, a lot of different Mikrodosiersystemen known in different fields.

STATE OF THE ART

In the field of inkjet printing technology is out of the EP 1 212 133 B1 a droplet generation by pressure effect, exerted by a driven via a positive displacement membrane or a plunger actuator known. In this case, self-filling rising capillaries are used as vertical metering lines in a print head, at whose lower ends are metering openings in which the fluid to be ejected is present. Self-filling climbing capillaries are for example also from the DE 101 23 259 A1 in which a Mikrodosiersystem is presented for microstructuring. Furthermore, from the EP 0 158 485 A2 a droplet generator is known in which fluid is pumped from a reservoir into a capillary as a dosing line. At the lower end there is a metering, which is arranged in the constriction of a venturi. Gas flowing through the venturi draws the drops out of the capillary, with the parameters of the gas and the venturi defining the drop parameters.

In the field of the production of EUV radiation (Extrem Ultraviolet), it is further for example from the US 6,493,423 B1 It is known to use free jet microdosing systems, which drip the finest fluid droplets into a chamber in which the droplets are then irradiated as targets by a laser pulse and generate EUV radiation. Another type of droplet generation in the field of EUV radiation is known from the DE 102 60 376 A1 in which supersaturated fluid vapor is passed under high pressure via a heatable expansion channel with a supersonic nozzle at its end. A pulsed electromagnetic valve releases the vapor into a vacuum chamber and forms liquid droplet targets upon cooling.

In the field of measurement technology, it is known from the prior art to use lasers in the droplet generation for the measurement of droplet parameters by detecting and evaluating different pulse parameters of a laser pulse after passing through the droplet (compare, for example JP 2006047235 A . DE 603 04 323 T2 ).

In the field of chemical analysis by detection of gaseous substances it is from the US 6,601,776 B1 It is known to pulse-heat a tubular reservoir tank filled with a pressurized medium so that there is a pulsed increase in pressure, and thus a discharge of droplets through openings in the reservoir tank. A similar arrangement is from the DE 10 2004 030 769 A1 for producing droplets in the femtoliter range, but the reservoir tank is divided into two by a pressure membrane under the action of a pressure source.

Also known in the field of chemical analysis is the so-called "laser ablation", in which solid or liquid target substances are evaporated in the smallest amounts by bombardment with a laser pulse and fed to a spectrometer. From the US 2006/0108538 A1 According to this method, the analysis of proteins is known, which were previously immobilized and then decomposed by bombardment with ultrashort laser pulses.

In addition is from the DE 690 10 410 T2 Also known to fix the substance to be examined by freezing on the substrate.

From the DE 28 37 799 A1 In addition, it is known to drip a fluid directly into a conveyor belt in a vacuum chamber by means of a microdispensing device with a micromembrane pump. On the conveyor belt, the drop is then moved into the focus of a laser and evaporated by a laser pulse. Alternatively, a continuous stream of gas can be directed onto the conveyor belt in the laser focus, while the conveyor belt serves to remove unevaporated residues. In a third embodiment, the drop is dripped freely into the vacuum chamber and evaporated by the laser pulse. The drops are generated by means of pressure pulses via a pressure membrane in the fluid reservoir, wherein the pressure pulse frequency is synchronized again with the laser pulse frequency. The generated molecules / atoms fly through a predetermined distance and are chromatographically detected with respect to their time of flight (TOF).

From the DE 3735787 C2 For example, a dropper sprayer is known in which a free fluid jet from a fluid reservoir leaks out through a nozzle and passes through a field of two ultrasonic vibrators. Both oscillators form a standing sound wave with common nodes. The fluid jet is atomized in a node.

The closest prior art from which the present invention is based is disclosed in U.S.P. DE 199 26 464 A1 disclosed. A microdosing system is described with the aid of which drops, there ink, as discrete quantities of fluid, diameters between 5 μm and 200 μm, are ejected contactlessly into a hollow cylindrical walled, few mm long flow channel. The flow channel is continuously flowed through by a pressurized carrier gas, for example air, which accelerates the drops and transports them to a substrate). The fluid is introduced axially from a fluid reservoir via a metering line which is dimensioned with respect to the drop dimensions and a metering opening in the flow channel from the end face thereof. The generator unit for the drops is an ultrasonic unit. The fluid jet emerging from the metering orifice is broken up into a high number (typically 64,000 / s) drops by means of ultrasound excitation and thereby charged electrically. Electric baffles then direct the drops onto the substrate to create a printed image.

TASK

The It is therefore an object of the present invention to provide an alternative microdosing system that is simpler Make gas clouds with low concentrated substances and a defined Frequency and duration of releases in a flow channel can deliver. The SOLUTION of the invention for this task is the main claim and the sibling Claim, advantageous developments of the invention are shown in the subclaims and below explained in more detail in connection with the invention.

The has a microdosing system according to the invention Formation of the dosing line as a self-filling rising capillary on, at least with the dosing, the wall of the Flow channel penetrates. In capillaries it is around tubes with very small inner diameters. By the strong compared to larger pipes in the Foreground surface effects increase liquids with high surface tension in capillaries automatically on (physical effect of capillarity). The end the ascending capillary is as narrowing nozzle opening educated. Since this is located in the flow channel, is the fluid to be dosed by the design of the riser capillary without further pumping technology in this rises, always automatically in the nozzle opening at the transition to the flow channel at. Furthermore, the generator unit is designed as a pulsed laser, its focus either on the nozzle opening or is aligned with the riser capillary. Here are the sent Laser pulses a variable energy larger as the evaporation energy of the fluid, so that in the nozzle opening Pending fluid at each impingement of a laser pulse as defined Gas cloud as a discrete amount of fluid in the flow channel is ejected. This is done either by direct energy input in the fluid when the laser focus directly on the nozzle opening is aligned. The gas cloud output can also be indirect can be achieved when the laser focus is aligned with the riser capillary is. Due to the generated pressure pulse in the riser capillary at Impact of the laser pulse, the fluid is in the flow channel ejected and evaporated there by relaxation behind the nozzle opening to a gas cloud as discrete Amount of fluid. This alternative is suitable for dosing of fluids whose evaporation energy is correspondingly low, but the surface tension is still for the Capillary effect must be sufficient.

In order to achieve the abovementioned object, the invention provides a microdosing system in which the fluid containing the substances contained is converted into the gas phase by means of a pulsed laser. For this purpose, the fluid is carried up by utilizing capillary forces in the riser capillary up to the metering and transported away from there by the carrier gas flowing in the flow channel. In this case, a gas cloud is generated in the dosing through direct laser bombardment or the fluid is ejected by indirect laser bombardment on the riser capillary through the pressure pulse generated in the capillary and thereby evaporates. By pulsing the laser, the frequency and duration of the gas clouds can be precisely defined. By changing the energy input by the laser pulse into the fluid fluids with different evaporation energies can be converted into the gas phase. Depending on the size of the evaporation energy, a direct or indirect laser pulse bombardment can take place, in particular fluids with low evaporation energy can be vaporized by indirect laser bombardment of the riser capillary, which reduces the risk of substance decomposition. Such microdosing with laser use for gas cloud formation offers the advantage of highly precise adjustability, so that gas clouds with different volumes can be generated with high precision and reproducibly up to the femtoliter range - even in their temporal appearance - and delivered into the flow channel. Especially for applications in the field of (bio) chemical analysis, the microdosing system according to the invention is thus particularly suitable.

Prefers The nozzle opening can be variable in diameter be. This can be done either by providing different Nozzles or by providing a nozzle opening with adjustable diameter, for example according to the iris principle, will be realized. Preferably, an array of multiple riser capillaries be provided, each nozzle openings a having different diameter. The concentration or size The generated gas cloud is then controlled by the Lasers regulated, with its laser focus then on the corresponding Aligned nozzle opening or riser capillary becomes. while determining the size of the nozzle opening the ascending capillary (microcapillary) as a function of the penetration depth of the laser light in the fluid to be evaporated the Quantity and concentration in the gas cloud that generates with a laser pulse becomes. In addition, using state-of-the-art microstructuring technology the ascending capillary are made so small and so accurate that reproducible volumes can be evaporated with high accuracy. At the nozzle opening of the riser capillary forms a drop of a certain size, which through the Surface tension and the diameter of the nozzle opening is determined. This drop is then affected by the impinging laser pulse vaporizes, where it is also possible for the the evaporation of the droplet also required energy input Apply several laser pulses.

Farther the microdosing system according to the invention can advantageously be carried out by an alignment of the laser focus on the nozzle opening with a diametrical arrangement of the laser relative to the Be marked nozzle opening. The laser pulses then traverse the flow channel exactly in diameter.

Of the Laser can also be at any other angle to the dosing be arranged, from which a laser focusing on the dosing is possible. For indirect excitation by laser pulse bombardment The ascending capillary allows the laser in any position, preferably laterally and there preferably orthogonal to the ascending capillary, outside be arranged the flow channel. In any case arises a very compact construction of the microdosing system according to the invention, especially even if preferred the riser capillary below the flow channel is arranged so that the fluid in the Rising capillary rises vertically. The gas clouds kick then streamlined in the lower center in the flow channel and are from the carrier gas, which preferably forms a laminar flow, detected and transported away (towards a detector). It will the flow channel preferably continuously from the carrier gas flows through. A pulsed flow is but also possible, where the frequency must of course be tuned to the frequency of the laser pulses or the gas clouds.

by virtue of the preferred laminar and continuous flow in the Flow channel carried the mass transfer of the generated Gas clouds between the flow layers by diffusion. To smear the pulse pattern within the flow channel due to these transport mechanisms curb or to can prevent, in the microdosing system according to the invention advantageously a Device for generating a flow direction Pressure wave may be provided in the flow channel. It is the frequency of the pressure wave so on the frequency of the pulsed laser tuned that any generated gas cloud in a low pressure area the pressure wave is concentrated. Always between two high pressure areas a gas cloud becomes coherent in a low pressure area transported, a smearing of the gas cloud is thereby safe prevented. In this case, preferably a sound source as a device be used to generate the longitudinal pressure wave. For example by the preferred use of an ultrasonic source with a Ultra sound frequency in the range 20 kHz and 1 GHz, in particular one Megasonic frequency between 400 kHz and 2 MHz, can be ultrasonic waves be generated, with the help of which the individual gas clouds with the contained substances by the local pressure differences in the flow channel kept separate from each other and transported so that a Mixing of the carrier gas and the gas cloud safely prevented becomes. The sound waves can be continuous or Pulsed be discharged into the flow channel.

The fluid may be liquid or gaseous in nature, so it will self-activate in the riser capillary rises. At the end of the riser capillary, the fluid at the nozzle opening is then transferred to the gaseous state or kept there, when the fluid is a gas, and introduced into the flow channel. In a preferred embodiment of the microdosing system according to the invention, it may also be provided to position a cooling element below the freezing point in the area of the nozzle opening for cooling the fluid present in the nozzle opening, the laser focus then being aligned with the nozzle opening. By the cooling element, the pending in the nozzle opening fluid is very local (possibly even. Only partially in the nozzle opening) transferred to the solid state, which in individual cases, especially depending on the substance contained in the fluid, may be advantageous since the The substance to be examined can then be better positioned in the dosing opening and thus better in the laser focus. By way of the cooling element, it is possible to achieve such a localized freezing that complete evaporation of the solid fluid is ensured, so that subsequently new fluid can flow in.

The Microdosing system according to the invention may be preferred as a pulsed laser have a semiconductor, solid state or gas laser, which can generate high pulse frequencies with high accuracy. Of the Use of the simplest laser diodes is also easy possible. By designing micro and nano channels the microdosing system according to the invention can be extremely be dimensioned compact. The nozzle opening can be a Veren movement of a cross section in the micron range have a cross section in the nm range. As a carrier gas can preferably air can be used. Inert gases that do not mix can go with the substances in the fluid, but can also be used. The fluid may preferably be a liquid or gaseous fluid of different evaporation energy from / with an ester, an ether, aromatics, aliphatic hydrocarbons, Lactones, alkaloids, organic solvents, fragrances or pheromones and / or a derivative or a mixture thereof act. As further preferred parameters for the microdosing system According to the invention, the generation of gas clouds can continue with volumes ranging from 1 fl to 10 ul, one Flow velocity in the range of 1 μm / s to 20 m / s, a laser wavelength up to a range of 10 .mu.m, in particular in the UV, VIS or IR range, a Repetition rate of the pulsed laser between 1 Hz and 1 GHz, a Frequency of gas clouds between 1 Hz and 100 kHz, one diameter the ascending capillary in a range of 10 μm and 1 mm, a diameter of the nozzle opening between 10 nm and 50 microns and / or a length of the flow channel up to 1 m. Further details on the microdosing system according to the invention are the following specific description part refer to.

In In practice, the microdosing system according to the invention may be preferred be used with a modular design. This is a first Module consisting of laser, fluid reservoir, supply lines for the carrier gas and flow channel and a second Module, consisting of riser capillary and nozzle opening, used. The components of the two modules are in theirs Parameter values variable. The modules can then vary depending on Use case can be used. In particular, the second module be exchanged according to requirement / application; various Modules can then z. B. different sized nozzle openings Offer.

Embodiment

forms of training The microdosing system according to the invention will be described below the schematic figures for further understanding of Invention explained in more detail. Showing:

1 a schematic of the microdosing system with laser-assisted generation of the gas clouds and

2 the microdosing system according to 1 with additional sound-enhanced concentration of gas clouds

The 1 shows the microdosing system 01 for non-contact introduction of gas clouds 02 as discrete quantities of fluid from a fluid reservoir 03 into a walled and of a carrier gas 04 flowed through the flow channel 05 according to the invention schematically in its entirety and in a magnification section (circle, only ALTERNATIVE A). The gas clouds 02 may preferably have volumes in a range from 1 fl to 100 ul, but volumes can also be produced in the range of 1 ml. The fluid may be a liquid or gaseous fluid of different vaporization energy, for example an ester, an ether, various aromatics, aliphatic hydrocarbons, lactones, alkaloids, organic solvents, fragrances or pheromones. Likewise, derivatives or mixtures thereof may be supplied to a detector, such as a mass spectrometer or a chromatograph, for biochemical analysis at the exit of the flow channel.

The fluid 06 becomes via a self-filling climbing capillary 07 as dosing in the flow channel 05 transferred. The climbing capillary 07 is preferably in a radial plane of the flow channel 05 and points to its central axis. The climbing capillary 07 may preferably have a diameter in a range of 10 microns and 1 mm, wherein the selected diameter is also dependent on the The fluid used (in the case of liquids, the capillary effect must occur due to the surface tension, gases can rise on their own) and can be above or below it. In the flow channel 05 , which may preferably have a length of between a few centimeters to 1 m, may be air as a carrier gas 04 which can flow at a flow rate in the range of 1 .mu.m / s to 20 m / s. This is the formation of a laminar flow 08 prefers. Also advantageous is a continuous flow through the flow channel 05 , At a very low discharge frequency of the gas clouds 02 , the preferred ejection frequency is between 1 and 100,000 releases per second, the flow may also be pulsed accordingly.

The climbing capillary 07 is outside the flow channel 02 and has a frontal, narrowing nozzle opening 09 as dosing on. Preferably, the narrowest diameter of the nozzle opening 09 be in a range between 10 nm and 50 microns. Through the nozzle opening 09 that the wall 10 of the flow channel 05 breaks through, become the gas clouds 02 in the flow channel 05 dismiss. In the embodiment shown, the riser capillary 07 below the flow channel 05 arranged so that the gas clouds 02 the flow channel 05 enter in the lower middle and so optimally from the carrier gas 04 can be included. The nozzle opening 09 can, for example, even into the middle of the flow channel 05 be guided, but here is sufficient rigidity of the riser capillary 07 and to look for a vortex avoidance in the channel flow. In the embodiment shown, the riser capillary 07 good in the wall 10 of the flow channel 05 supported and therefore can be flexible outside as well.

To generate the discrete gas clouds 02 is in the microdosing system 01 according to the invention, a pulsed laser 11 as - also outside the flow channel 05 lying - generating unit used. This may be, for example, a semiconductor, solid state or gas laser. CO ₂ gas lasers, for example, generate laser pulses with high accuracy and creep resistance 12 into the fs area. A repetition rate of the pulsed laser is preferred 11 between 1 Hz and 1 GHz and a laser wavelength up to a range of 10 .mu.m, in particular in the UV, VIS or IR range used. In this case, the laser pulses 12 a variable energy content that is greater than the evaporation energy of the in the nozzle opening 09 upcoming fluid. The focus 13 the laser 11 is in the illustrated embodiment (ALTERNATIVE A) directly on the nozzle opening 09 the climbing capillary 07 aligned, so that in the nozzle opening 09 Pending fluid at each incident laser pulse 12 a gas cloud 02 directly into the flow channel 05 evaporated. Furthermore, in the embodiment shown, the laser 11 diametrically opposite the nozzle opening 09 arranged so that the laser pulses 12 the flow channel 05 go through the center along its diameter.

Optionally, with a focus 13 the laser 11 directly on the nozzle opening 09 (ALTERNATIVE A) nor a cooling element, such as a Peltier element, be arranged that the impending fluid freezes locally limited, so that an improved laser bombardment is possible (in 1 not shown). By the laser pulse 12 Due to its chosen energy content, all of the solid, frozen fluid is vaporized, allowing new fluid into the nozzle orifice 09 can flow.

In the ALTERNATIVE B in 1 is an arrangement of the laser 11 laterally from the riser capillary 07 and in particular orthogonal to it. The focus 13 the laser 11 is now on the climbing capillary 07 aligned so that the laser pulses 12 on the climbing capillary 07 impinge and in their interior trigger a pressure pulse, whereby each fluid (in volatile form) as a gas cloud 02 from the nozzle opening 09 in the flow channel 05 is ejected.

In the 2 is a schematic sound source 20 for generating a flow direction 21 extending pressure wave 22 in the flow channel 05 shown, causing smearing of the gas clouds 02 in the laminar flow 08 in the flow channel 05 can be avoided. Here is the frequency of the pressure wave 22 so on the frequency of the pulsed laser 11 is tuned that every gas cloud generated 02 in a low pressure area 23 between two high pressure areas 24 the pressure wave 22 is concentrated. Preferably, it has the sound source 20 an ultra-sound frequency in the range 20 kHz and 1 GHz, in particular a megasonic frequency between 400 kHz and 2 MHz.

Due to the small dimensions of the microdosing system 01 according to the invention in the form of micro and nanochannels (flow channel 02 , Climbing capillary 07 ) and the controllable energy input by means of a laser 11 This concept enables the highly accurate, adjustable dosage of dilute and undiluted fluids 06 in the form of gas clouds 02 with discrete quantities down to the pico and femtogram range with a defined frequency and pulse duration. This is the microdosing system 01 According to the invention particularly suitable for applications in the chemical and biotechnological field.

For example, for analysis as volatile liquid for evaporation butyl acetate having an enthalpy of vaporization of about 40 kJ / mol, a density of 0.88 g / mol and a molecular weight of 116 g / mol are used. The riser capillary can have a diameter of 20 .mu.m and the nozzle orifice a diameter of 2 .mu.m (narrowing 10: 1). The flow channel may have a diameter of 2 mm and a length of 10 cm. Therefore, the components used are microcomponents. For evaporation, a pulsed IR laser with 1200 nm wavelength and a power of 1 W can be used.

The opening of the ascending capillary (microcapillary) allows an ideal spherical volume of 4.2 μm ³ (1 μm radius), corresponding to 4.2 fl (femtoliters). In this volume are 4.3 · 10 ^-10 mol of n-butyl acetate, which is to be evaporated with a laser pulse. The energy required for this is 17 μJ, ie the laser pulse with a power of 1 W must be 17 μs long in order to apply the corresponding energy (P = 1 W, E = 1.7 · 10 ^-5 J, → t _pulse = E / P = 17 μs). In this case, the carrier gas flows, for example, at 0.5 m / s through the flow channel; the repetition rate of the laser should be 200 Hz, then a mean distance of the vaporized gas clouds of 2.5 mm sets in (all numerical values given are only reference values for corresponding value ranges).

01

micro-dosing system

02

gas cloud

03

fluid reservoir

04

carrier gas

05

flow channel

06

fluid

07

Steigkapillare

08

laminar flow

09

nozzle opening

10

wall

11

pulsed laser

12

laser pulse

13

laser focus

20

sound source

21

flow direction

22

shock wave

23

Low pressure area

24

Anticyclone

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1212133 B1 [0003]
• - DE 10123259 A1 [0003]
• EP 0158485 A2 [0003]
• US 649342361 [0004]
• DE 10260376 A1 [0004]
• - JP 2006047235 A [0005]
• - DE 60304323 T2 [0005]
• - US 6601776 B1 [0006]
• - DE 102004030769 A1 [0006]
• US 2006/0108538 A1 [0007]
• - DE 69010410 T2 [0008]
• - DE 2837799 A1 [0009]
• - DE 3735787 C2 [0010]
• - DE 19926464 A1 [0011]

Claims (15)

Microdosing system ( 01 ) for non-contact introduction of discrete quantities of fluid from a fluid reservoir ( 03 ) in a walled and by a carrier gas ( 04 ) flowed through the flow channel ( 05 ) via a metering line with an end-side metering opening by means of a generator unit for generating the discrete fluid quantities, wherein the metering line and the generator unit outside the flow channel ( 05 ) are arranged, characterized by a design of the dosing as self-filling riser capillary ( 07 ), at least with the metering orifice, which as a narrowing nozzle orifice ( 09 ) is formed, the wall ( 10 ) of the flow channel ( 05 ) and a formation of the generator unit as a pulsed laser ( 11 ) whose focus ( 13 ) on the nozzle opening ( 09 ) or on the riser capillary ( 07 ) and whose emitted laser pulses ( 12 ) a variable energy greater than the evaporation energy of the fluid ( 06 ), with each laser pulse ( 12 ) a gas cloud ( 02 ) in the flow channel ( 05 ) is initiated. Microdosing system according to claim 1, characterized by a variable diameter of the nozzle opening ( 09 ) or an array arrangement of several ascending capillaries ( 07 ) with nozzle openings ( 09 ) of different diameters. Microdosing system according to claim 1, characterized by an alignment of the laser focus ( 13 ) on the nozzle opening ( 09 ) with a diametrical arrangement of the pulsed laser ( 11 ) opposite the nozzle opening ( 09 ). Microdosing system according to claim 1, characterized by an alignment of the laser focus ( 13 ) on the riser capillary ( 07 ) with an orthogonal arrangement of the pulsed laser ( 11 ) to the ascending capillary ( 07 ). Microdosing system according to claim 1, characterized by an arrangement of the rising capillary ( 07 ) below the flow channel ( 05 ). Microdosing system according to claim 1, characterized by a laminar flow ( 08 ) of the carrier gas ( 04 ) in the flow channel ( 05 ). Microdosing system according to claim 1, characterized by a device for generating a in the direction of the flowing carrier gas ( 04 ) (Flow direction ( 21 )) running pressure wave ( 22 ) in the flow channel ( 05 ), the frequency of the pressure wave ( 22 ) so on the frequency of the pulsed laser ( 11 ) that each generated gas cloud ( 02 ) in a low pressure area ( 23 ) of the pressure wave ( 22 ) between two high pressure areas ( 24 ) is concentrated. Microdosing system according to claim 7, characterized by a sound source ( 20 ) as a device for generating the flow direction ( 21 ) extending pressure wave ( 22 ). Microdosing system according to claim 1, characterized by a cooling element in the region of the nozzle opening ( 09 ) for cooling the in the nozzle opening ( 09 ) pending fluid ( 06 ) below the freezing point, the laser focus ( 13 ) on the metering opening ( 09 ). Microdosing system according to claim 1, characterized by a semiconductor, solid-state or gas laser as a pulsed laser ( 11 ). Microdosing system according to claim 1, characterized by air as carrier gas ( 04 ). Microdosing system according to claim 1, characterized by a liquid or gaseous fluid ( 06 ) different evaporation energy from / with an ester, an ether, aromatics, aliphatic hydrocarbons, lactones, alkaloids, organic solvents, fragrances or pheromones and / or a derivative or a mixture thereof. Microdosing system according to claim 1, characterized by gas clouds ( 02 ) having a volume in a range of 1 fl to 10 ul, a flow rate in the range of 1 .mu.m / s to 20 m / s, a laser wavelength up to a range of 10 .mu.m, in particular in the UV, VIS or IR range , a repetition rate of the pulsed laser ( 11 ) between 1 Hz and 1 GHz, a frequency of the gas clouds ( 02 ) between 1 Hz and 100 kHz, a diameter of the ascending capillary ( 07 ) in a range of 10 microns and 1 mm, a diameter of the nozzle opening ( 09 ) between 10 nm and 50 μm and / or a length of the flow channel ( 05 ) not equal to zero up to 1 m. Microdosing system according to claim 7, characterized by an ultra-sound frequency in the range of 20 kHz and 1 GHz, in particular a megasonic frequency between 400 kHz and 2 MHz. Microdosing system according to claim 1 and / or 7, characterized by a modular construction with a first module consisting of laser ( 11 ), Fluid reservoir ( 03 ), Supply lines for the carrier gas ( 04 ) and flow channel ( 05 ), and a second module consisting of riser capillary ( 07 ) and nozzle opening ( 09 ), whereby the components of the two modules are variable in their parameter values.