ES2277707A1 - Method and device for the production of liquid aerosols and use thereof in analytical atomic and mass spectrometry - Google Patents

Abstract

The invention relates to a device and method for the atomisation or nebulisation of a liquid for spectrometric analysis, using a propellant gas which is introduced into the device under pressure. According to the invention, the two fluids are mixed together and subsequently released to the exterior, such that the liquid is released in the form of an aerosol or a suspension of drops that is conveyed by the gas stream. The aim of the invention is to produce a nebuliser for use in inorganic atomic and mass spectroscopic analysis with the following properties: a) low liquid and gas flow rate, b) robust materials and operation, c) ease-of-use, d) good drop-size control, and e) generation of fine, monodispersed aerosols.

Description

Procedure and device for production of liquid aerosols and their use in analytical (atomic spectrometry) and mass).

Object of the invention

The process of the present invention allows the aerosolization of a sample of liquid for introduction and analysis in an atomic spectroscopy system and / or of masses To do this, the liquid outlet is forced through an ejection nozzle located inside a pressure chamber equipped with a round outlet opening, open to the outside and located frontally before said ejection nozzle; the liquid driven advances in the form of capillary jet outwards with a stable liquid-gas interphase and leaves the camera then experiencing an instability process that fragments it into microdrops. Upon leaving, the spray is exposed to an external environment that produces a phenomenon measurable and characteristic chemical-physical capable of be used for qualitative and / or quantitative analysis. One of The main features of the invention is controlled obtaining and reproducible of a fine and homogeneous spray.

State of the art

An outstanding field of application of fogging devices is the development of systems introduction of liquid samples for elemental analysis by spectroscopic techniques ("flame atomic absorption spectrometry ", FAAS," inductively coupled plasma-optical emission spectrometry ", ICP-OES or ICP-AES, and "inductively coupled plasma-mass spectrometry ", ICP-MS). In all these analytical techniques the most used nebulizer is the so-called pneumatic type (concentric or cross flow), in which a gas stream at pressure is the cause of superficial instabilities that They allow to generate a spray. This type of nebulizer has been very used, mainly for its robustness and ease of handling; however, it presents some limitations that have made it necessary the development of other aerosol generation systems with analytical purposes; Among them, the most used is the nebulizer ultrasonic and, more recently, the "electrospray". Such systems, although they have advantages, also have important limitations, such as its high cost and difficulty of handling, or its unsuitable for certain types of samples (e.g., high saline content). However, they all continue to present some limitations that make the development of a most universal nebulizer that combines the largest number of advantages of the other nebulizers with the least number of their limitations This is the proposal of the new technology "Flow Focusing ", FF.

In all spectroscopic techniques used for inorganic elemental analysis use is made of a flame or plasma to give rise to various processes in the sample, such as the desolvation-vaporization-atomization-ionization-excitation. Common condition for such techniques is the presence of atoms or ions. liable to absorb or emit characteristic radiation or the ion quantification, characterized on the basis of its mass / load ratio (m / z). The first are called atomic absorption or emission techniques; the second make up the field of mass spectrometry applied to elementary analysis inorganic. In practically all the techniques a previous phase of atomization of the sample, in dissolution phase, object of analysis Thus, for example, the spectroscopy of atomic absorption with flame (FAAS) is very common and reliable for detection and quantification of metals and metalloids in samples of environmental origin and biological fluids (blood serum, urine, etc.). The sample is aspirated, converted into an aerosol and mixed with gases, such as air / acetylene or nitrous oxide / acetylene; then ignition of the gas mixture occurs producing a flame whose temperature varies between 2100ºC and 3200ºC. Other technologies of Elemental analysis of liquid samples do not require nebulizers, for example, absorption spectrophotometry Atomic with graphite furnace (GFAAS).

In recent years they have experienced a significant increase in its use of analytical techniques based on plasmas (ICP-AES and ICP-MS). With Both analysis techniques, if the sample is solid, is usually dissolved and mixed with a gas before being subjected to the action of plasma. Under this action, the drops undergo the processes of desolvation- vaporization-atomization-ionization-excitation in the brief moments of permanence of the same within the plasma. Thus, when plasma is used as a source of excitation, the technique is known as ICP-AES, and when it is used as a source of ionization it is about ICP-MS. For the quantitative analysis, in the first of the techniques the number of photons emitted by the excited atoms or ions of the analytes while in the second the number of ions thereof is measured. The techniques based on analytical plasmas present a series of advantages that make them very interesting in analytical laboratories; between them find: (i) low detection limits; (ii) wide range linear; (iii) multielemental analysis capacity; (iv) speed of the analysis; (v) possibility of making determinations of isotopic relationships; (vi) versatility and ease of automation.

Despite the years since its beginnings and intensive efforts in research and development made, the module for introducing liquid samples is still the weak point in dedicated spectroscopic techniques to the inorganic elemental analysis described above. Is Frequently, only a small percentage of the sample reaches be exposed to the atomizer (5-10% in flame and 1-2% in plasma). The introduction module of Sample usually consists of two separate stages: a) the generation of aerosol; b) drop selection. The first occurs in the nebulizer while the second one does it in the chamber of fogging and / or desolvation system.

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In pneumatic nebulization the sample can be provided in two different ways: (i) by free aspiration; (ii) by forced aspiration. In the first the sample is sucked by Venturi effect of the gas used to generate the aerosol, while in the second the sample is aspirated, usually at values close to 1 mL / min, using a peristaltic pump or some similar device that ensures a constant flow of Sample, regardless of its characteristics.

When the drops are greater than 8-10 µm, the atomization sources used (llamas and plasmas) are unable, in the short time interval that lasts the passage of the drops through the atomizer, to trigger all the processes that allow leaving atoms or ions ready to emit radiation (ICP-AES) or be introduced and separated in the mass spectrometer (ICP-MS). Therefore, the function of the fogging chamber consists of filter the drops larger than 15 µm. Another important function of the camera consists of damping the pump pulses peristaltic that would be reflected in the signal, deteriorating the Analysis accuracy Hence, when systems are used nebulization in analytical spectroscopy, be highly recommended generate aerosols as thin as possible. This would increase the analyte transport through the nebulization chamber and, in addition, plasma processes would be favored, all of which would eventually lead to increased sensitivity of the technique.

The process of generating an aerosol, in general, can be considered to be caused by instability produced on the surface of a liquid vein. Fogging systems can be classified according to the way (or type of energy used) to generate such instability. Instability can be generated: (i) by means of a gas under pressure, in the case of pneumatic nebulizers; (ii) by applying an electric field ("electrospray"); (iii) by the pressure exerted on a liquid mass when passing through a narrowing (high pressure hydraulic nebulizer); (iv) by ultrasonic energy (ultrasonic nebulizers); (v) by other systems (rotary or centrifugal, conventional or microwave thermal nebulizers, etc.): see, for example, (i) Boumans, PWJM, (ed.), " Inductively Coupled Plasma Emission Spectroscopy ", two volumes, Wiley , 1987; (ii) Montaser, A. (ed.), " Inductively Coupled Plasma Mass Spectrometry ". Wiley, 1998; (iii) Montaser, A. and Golightly, DW, (eds.), " Inductively Coupled Plasmas in Analytical Atomic Spectrometry ", 2nd edition. VCH, 1992; (iv) Todolí, JL; Mora, J .; Hernandis, V. and Canals, A., " Systems of Introduction of Liquid Samples in Atomic Spectrometry ", Secretariat of Publications of the University of Alicante, 1996.

The pneumatic nebulizers have two important configurations: (i) concentric; (ii) cross flow. In the first, the liquid stream is transported to the tip of the nebulizer through a concentric capillary tube with the misting gas conduction. The aerosol is formed in the capillary nozzle These nebulizers provide a excellent sensitivity and stability, especially if the Solution is clean. However, they may present problems of blocking when working with samples with high saline contents or suspensions In addition, analyte transport efficiency is found in the range of 1-10% according to the technique analytical (5-10% in FAAS and 1-2% in ICP-AES and ICP-MS). In the techniques based on plasmas the concentric nebulizers are usually of glass. Cross flow nebulizers consist of two capillaries placed perpendicularly and for each of them comes out the liquid sample to be nebulized and the gas of nebulization. The capillary liquid outlet is in an upright position and that of mist gas outlet forms an angle of 90º with respect to of the liquid. Generally, the liquid is expressly driven by a peristaltic pump. Cross flow nebulizers they are not as efficient in creating microdroplets but they ensure a more robust and less prone to blockage. A pneumatic nebulizer especially suitable for increasing the analyte transport is the so-called injection nebulizer direct ("Direct Injection Nebulizer", DIN). Said nebulizer generates the aerosol pneumatically at the base of the plasma so that the analyte transport is 100%, which is reflected in some significant improvements in sensitivity.

Recently, due to the need to analyze smaller amounts each see sample (biological fluids, samples of high added value ...) the need for design new pneumatic nebulizers that allow working at flows of the order of a few hundred, or less, of µL / min. These are called micronebulizers. It has also developed a direct injection micronebulizer (DIHEN). Although these nebulizers significantly improve transport analyte, because of their dimensions they are very prone to blockage and their Management is complex.

There are numerous additional modalities of nebulization, such as parallel flow nebulizer, suitable for liquids with inert solids in suspension; the CMA nebulizer (Concomitant Metals Analyzer), specially adapted to measurements environmental, where concentrations are very low; the nebulizer  JY tire, suitable for abrasion metals in oils

On the other hand, it is currently possible to produce a continuous stream of micro-drops or homogeneous and controllable microbubbles by means of a technology known as "focused flow"("FlowFocusing", or FF). The procedure for this requires a mechanical installation of great simplicity, as indicated in various publications of the sector (see, for example, Gañán-Calvo 1998, Phys. Rev. Lett ., Vol. 80, p. 285). Through this technique, a liquid capillary microchorro is produced, this being focused by the simultaneous and enveloping flow of a gas that coaxially travels with the aforementioned liquid jet. The liquid microbead thus formed undergoes a capillary rupture (see Chandrasekhar 1961 "Hydrodynamic and Hydromagnetic Stability", p. 541) after being expelled outside through the exit hole of the device. This phenomenon is finding potential fields of application in numerous technological fields: biomedicine, pharmaceutical industry, food and microengineering (photonic crystals, fibers, microbubbling ...).

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US-6 119 953 presents a liquid atomization procedure based on technology FF; given the importance of this reference, of which the current development is a subsequent derivation, the aforementioned will be used patent (D1) as a starting reference in the claims of The present invention.

The present invention aims to combine the advantages of a simple and robust design with specialization in micro samples. To that end, and based on the mechanism described in references on FF, an operation mode is selected that achieves the production of a very fine, homogeneous spray and reproducible. This increases the transport of dissolution to plasma which favors the analytical signal. In addition, the fact that the liquid vein does not come into contact with the walls of the exit of the nebulizer prevents the blockage of the same for depositions of analyte residues or particles in suspension. On the other hand, effective control of free surfaces in the spray generation zone by the optimal selection of duct and chamber materials that are found in contact with the liquid streams (sample) and gas (auxiliary) used for the generation of drops.

Description of the figures

Figure 1: Detail of a device nebulization of a liquid sample, according to the present invention, where they are detailed:

(one)

feed channel;

(2)

ejection nozzle;

(3)

pressure chamber;

(4)

exit hole.

Figure 2: Device according to the embodiment described in the text (chapter " Form of Embodiment of the Invention "), detailing:

(3)

pressure chamber;

(4)

exit hole;

(5)

tube gas feeder;

(6)

commercial two connector tracks;

(7)

gas or air source compressed;

(8)

tube ejection

(9)

side hole adjusted to ejection tube dimensions through the tube wall gas feeder;

(10)

form clamping piece cylindrical-conical;

(eleven)

through holes drilled in the clamp.

(12)

gas feed hole to the pressure chamber.

Figure 3: View of an analysis device liquid samples using a spectrometry instrument Atomic / Masses using a fogging device sample according to the present invention, in which are detailed:

(one)

feed channel;

(2)

ejection nozzle;

(3)

pressure chamber;

(4)

exit hole;

(13)

fogging chamber

(14)

Torch

(fifteen)

plasma

(16)

analyzer / detector system

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Description of the invention

The object of the present invention is a device and method of atomization or nebulization of a liquid subject to spectrometric analysis by using a impeller gas that is pressurized into said device. Both fluids are expelled outside after mixing, producing the exit of the liquid in the form of aerosol or suspension of droplets dragged by the gas stream.

The objective pursued is the achievement of a nebulizer, intended for use in spectroscopic analysis inorganic (atomic and mass), to ensure the following properties:

\;

Escaso caudal líquido y gaseoso\ circ

 \; 

Low liquid and gas flow

\;

Robustez de materiales y de manejo\ circ

 \; 

Robustness of materials and handling

\;

Facilidad de uso\ circ

 \; 

Easy to use

\;

Alto control del tamaño de gota\ circ

 \; 

High drop size control

\;

Generación de aerosoles finos y mono-dispersos\ circ

 \; 

Generation of fine and mono-dispersed aerosols

The process of the present invention allows the impulsion of a liquid from a channel of feeding (1). The liquid is a solution in which it is present as a solute a sample whose elements are to be subjected to inorganic spectrometric analysis. The force is forced liquid outlet through an ejection nozzle (2) located inside a pressure chamber (3) equipped with an orifice of round section outlet (4) open to the outside, said being hole located frontally before said ejection nozzle of liquid (2); the driven liquid advances with a flow rate Q towards the outside of said chamber (3) crossing the distance between said ejection nozzle and said outlet opening in the form of hair jet, with a stable interphase liquid-gas; gas is also forced to abandon said chamber through said exit hole, experiencing a pressure drop ΔP, and exerts dynamic efforts on said interphase; such dynamic efforts exerted by the gas not destabilize said capillary jet inside the chamber; said jet leaves the chamber then experiencing a process of instability that leads to its fragmentation in micro drops to form an aerosol. Upon leaving said chamber (3), said aerosol is transported through the fogging chamber or desolvation system to the plasma where the drops remnants experience the processes of desolvation-vaporization-atomization-onization-excitation.

One of the main features of the invention is the reproducible and controlled obtaining of a fine aerosol, whose drops are less than 15 microns in diameter. To do this, the flow rate Q of liquid, expressed in consistent units, must be less than 250 times the square root of the quotient between the fourth power of the surface tension of the liquid γ and the product of the density of the liquid \ rho_ {l} by the third power of the fall of gas pressure ΔP, that is:

Q \ leq 250 \ left (\ frac {\ gamma ^ {4}} {\ rho_ {l} \ Delta P3} \ right) ^ {1/2}

The device and the procedure object of the This invention facilitates the continuous obtaining of a Very fine and homogeneous spray. A light pressurization is enough to boost the fluid mixture and ensure the liquid atomization.

In a variant form of the invention, the ejection nozzle material (2) and the outlet hole (4) it can be ceramic or, alternatively, a polymer.

Another variant of interest is characterized by the fact that The body of the nebulizer has an elongated shape that allows its direct insertion into the torch, which allows to introduce the spray directly at the base of the plasma.

It is also possible to design a system multimicronebulizador that combines in a head numerous systems Nebulizers as described above. This is necessary divide the aqueous sample into a number greater than two streams liquids, each of which is directed towards a nozzle of ejection and a separate outlet hole, the regime of flow and spray formation conditions in each ejection nozzle similar to the above.

A design option includes the inclusion of a connection to an analytical desolvation system. This one can be of the conventional type, based on heating stages and condensation by cooling, or more advanced type, combining a heating stage with the passage through membranes, said being porous or non-porous type membranes.

Another variant of interest includes the possibility of coupling the nebulizer to a separation system as a stage prior to the qualitative, quantitative or elementary determination combined by atomic spectroscopic techniques, the dynamic separation techniques used (chromatographic or electrophoretic).

Embodiment of the invention

A nebulizer device for generating a fine aerosol intended for spectrometric analysis as described in the claims can be realized in particular as follows. A gas feeder tube (5) is provided whose walls are of a hydrophobic material, for example, Teflon; the dimensions of said tube are 6 mm outside diameter and 4 mm inside diameter Said gas supply tube may have a total length of 6 cm. One end of said tube is joined by a commercial two-way connector (6) (for example, of the provided by the Legris brand) to a gas or air source tablet (7). The opposite end is closed by a plug (8) whose inner bottom is flat or hemispherical (or otherwise similar), a hole (4) having been drilled in said bottom guideline coinciding with the axis of said feeder tube (5), the walls of said hole being conical, open towards the outside of said nebulizer. The minimum diameter of said exit hole (4) can be chosen from 5 µm.

On the other hand, a solution is available aqueous composed of the sample under analysis; bliss dissolution comes from a feed channel (1); bliss aqueous solution is mechanically forced to move through a tube ejection (9), also made of a hydrophobic material, for example Teflon. The diameter of said ejection tube (9) is considerably smaller than the inside diameter of said tube gas feeder (5); for example, a value of 0.35 mm for the internal diameter and 0.8 mm for the external diameter. The final section of said ejection tube (9) penetrates, by a side hole (10) adjusted to the dimensions of the tube ejection (9), through the wall of the gas supply tube (5). The end of the ejection tube (9) opposite the channel of feed (1) is open and constitutes an ejection nozzle (2), coaxially located with the axis of the feeder tube and arranged frontally before the exit hole (4), a distance that can be established between nozzle and hole be chosen of 0.1 mm. Said ejection nozzle (2) is maintained in position with respect to the walls of the plug (8) and with respect to the hole (4) by means of a clamping piece (11), so cylindrical-conical, which defines a pressure chamber (3). The front part of said clamping piece (11) is essentially cylindrical and fits laterally to the walls plug interiors (8); the back, closer to exit hole (4) and at the bottom of the plug (8), it is shaped conical The angle formed by any generatrix, from the vertex of said cone, and the axis of said feeder tube (5) in the sense of advance of the gas stream, is obtuse (?> 90º). The ejection nozzle protrudes from the apex of said cone, advancing with a small overhang, for example, 0.5 mm

The gas from the power supply (7) travel inside the feeder tube (5) and access the chamber (3) through one or more through holes (12) perforated in said clamping piece (11). The driven liquid advances towards the outside of said chamber (3) crossing with a flow Q the distance between said ejection nozzle and said outlet hole (4) in the form of a capillary jet, with a stable liquid-gas interphase; the gas is likewise forced to leave said chamber through said orifice of output, experiencing a pressure drop ΔP, and exerts dynamic efforts on said interphase; such efforts dynamic exerted by the gas do not destabilize said jet capillary inside the chamber; said jet leaves the camera then experiencing an instability process which leads to its fragmentation into microdroplets to form a aerosol. The material of said cap (8) is chosen so that it is immediate evacuation of electric charges produced in the inner surface thereof due to friction in the layer limit formed by circulating gas; in particular, it can be chosen as Teflon reinforced with carbon fiber.

The remaining aspects of the device are They conform generically to the description previously made. The liquid it is a solution in which a sample is present as solute whose elements have to be subjected to inorganic analysis spectrometric using plasma-based techniques as a source of atomization / ionization / excitation; upon leaving said chamber to pressure (3), said aerosol passes through a fogging chamber or desolvation system until you reach a plasma area where the atoms formed are either excited or ionized by the high plasma temperatures, the magnitude being quantified or the emission of photons of characteristic wavelength of each element / ion or the number of ions with a given relationship mass / load (m / z), depending on the mode of quantification Used in the analysis. Said liquid flow rate Q is lower, in consistent units, at 250 times the square root of the quotient between the fourth power of the surface tension of the liquid γ and the product of the density of the liquid \ rho_ {l}, by the third power of the gas pressure drop ΔP, this is:

Q \ leq 250 \ left (\ frac {\ gamma ^ {4}} {\ rho_ {l} \ Delta P3} \ right) ^ {1/2}

The device object of the present invention It has the following advantages:

one.

He generated droplet size is particularly small and can be predict accurately;

2.

Getting aerosols practically monodispersed;

3.

Very reduced sample consumption (of the order of microliters by minute);

Four.

He liquid jet does not come into contact with the orifice walls of output, thereby preventing blockage by deposition of salts or suspended particles;

5.

high sensitivity for components present in low concentration (low values of detection limits, LOD).

6.

Great chemical and mechanical robustness;

7.

Ease of handling and maintenance;

8.

Precision in the geometry of free surfaces secured by using materials hydrophobes;

9.

Evacuation of electrostatic charges originated on the surface of the interior walls, where the viscous friction with the focusing gas stream determines local electrification processes. For this you can resort to use a material with conductive aptitude.

In the attached table, the performance of some common nebulizer models in Atomic Spectroscopy / Masses

one

In reference to the sample size, it should be noted that the Conikal device needs a sample quantity 10 times larger than the other two. On the other hand, the device with Flow-Focusing technology is an order of magnitude more sensitive than the Conikal model and up to 20% more sensitive than the HEN model. Finally, the pressure necessary to achieve the nebulization is 2 to 4 times higher in the HEN.

Claims (11)

1. Nebulizer device for the generation of a fine aerosol for the spectrometric elementary analysis of a sample present as a solution from a feed channel (1); said solution is forced out through an ejection nozzle (2) located inside a pressure chamber (3), whose walls constitute the body of said nebulizer; said chamber is provided with an outlet opening (4) open to the outside; said hole is located frontally before said liquid ejection nozzle (2); characterized in that a gas supply tube (5) is provided; one end of said tube is connected by a commercial two-way connector (6) to a source of gas or compressed air (7); the opposite end is closed by a plug (8) whose inner bottom is flat, hemispherical or otherwise similar, the outlet opening (4) whose guideline is coincident with the axis of said feeder tube being perforated with circular section in said bottom (5), the walls of said hole being conical, open towards the outside of said nebulizer; the solution is mechanically forced to move through an ejection tube (9), the diameter of said ejection tube (9) being considerably smaller than the inside diameter of said gas feed tube (5); the final section of said ejection tube (9) penetrates, through a side hole (10) adjusted to the dimensions of the ejection tube (9), through the wall of the gas supply tube (5); the end of the ejection tube (9) opposite the feed channel (1) is open and constitutes an ejection nozzle (2), located coaxially with the axis of the feed tube and arranged frontally before the outlet orifice (4); said ejection nozzle (2) is held in position with respect to the walls of the plug (8) and with respect to the hole (4) by a clamping piece (11), cylindrical-conical, which defines, together with the interior walls of said plug (8), said pressure chamber (3); the front part of said fastener (11) is essentially cylindrical and fits laterally to the inner walls of the plug (8); the rear part, closest to the outlet opening (4) and the bottom of the cap (8), is conical in shape; the angle a formed by any generatrix, from the apex of said cone, and the axis of said feeder tube (5) in the direction of advance of the gas stream, is obtuse (α> 90 °); the ejection nozzle protrudes from the apex of said cone, advancing with a small length overhang; The gas from the power supply (7) travels inside the feeder tube (5) and accesses the chamber (3) through one or more through holes (12) drilled in said clamp (11). 2. Nebulizer device according to claim 1, characterized in that the material of the ejection nozzle (2) and that of the outlet orifice (4) is ceramic and / or polymeric. Device according to claims 1 to 2, characterized in that said nebulizer body has an elongated shape that allows the tip of the nebulizer (8) to be approximated to the base of the plasma through the torch (14) Device according to claims 1 to 3, characterized in that at least one of the inner walls of the ejection nozzle (2), the pressure chamber (3) or the outlet orifice (4) are made of hydrophobic material, in particular Teflon . Device according to claims 1 to 4, characterized in that the inner walls of the pressure chamber (3) or the outlet orifice (4) are of material suitable for the evacuation of the accumulated load by friction of the circulating gas in the boundary layer of contact formed in the interface with said interior walls. 6. Device according to claim 5 characterized in that said material is carbon reinforced Teflon. 7. Device according to claims 1 to 6, characterized in that the liquid sample is divided into a number greater than two liquid streams, each of which is directed towards an ejection nozzle and a separate outlet orifice. 8. Device according to claims 1 to 7 characterized in that it includes a connection to an analytical desolvation system. 9. Device according to claims 1 to 8, characterized by the possibility of being coupled to a separation system as a stage prior to its qualitative, quantitative or combined elementary determination using Atomic / Mass Spectroscopic techniques, the separation techniques being used dynamically. 10. Device according to claim 9 characterized in that the separation techniques used are chromatographic or electrophoretic. 11. Procedure for obtaining an aerosol by driving a liquid from a feed channel (1), forcing its exit through an ejection nozzle (2) located inside a pressure chamber (3) equipped with an outlet opening (4) open to the outside; said hole (4) is located frontally before said liquid ejection nozzle (2); the driven liquid advances towards the outside of said chamber (3) crossing with a flow rate Q the distance between said ejection nozzle (2) and said outlet orifice (4) in the form of a capillary jet, with a stable liquid-gas interphase ; the gas is also forced to leave said chamber through said outlet orifice (4), experiencing a pressure drop ΔP, and exerts dynamic stresses on said interphase; said dynamic forces exerted by the gas do not destabilize said capillary jet inside the chamber (3); said jet leaves the chamber (3) then undergoing an instability process that leads to its fragmentation into microdroplets to form an aerosol; at its exit from said pressure chamber (3), said aerosol passes through a fogging chamber (13) or desolvation system until it reaches a plasma zone (15) where the formed atoms are either excited or ionized by the high plasma temperatures, being the quantified magnitude or the emission of photons of characteristic wavelength of each atom / ion or the number of ions with a given mass / charge (m / z) ratio of a given element, depending on the modality of quantification used in the analysis; characterized in that the liquid to be analyzed is a solution in which a sample is present as a solute whose elements have to be subjected to inorganic spectrometric elementary analysis by means of plasma-based techniques as a source of atomization / ionization / excitation; said exit hole is of round section; The liquid sample is supplied with a liquid flow rate Q which is less, in consistent units, at 250 times the square root of the quotient between the fourth power of the liquid surface tension and the product of the liquid density p, by the power third of the gas pressure drop ΔP, this is: Q \ leq 250 \ left (\ frac {\ gamma ^ {4}} {\ rho_ {l} \ Delta P3} \ right) ^ {1/2}