Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
  • B05B7/02—Spray pistols; Apparatus for discharge
  • B05B7/06—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane
  • B05B7/062—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane with only one liquid outlet and at least one gas outlet
  • B05B7/066—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane with only one liquid outlet and at least one gas outlet with an inner liquid outlet surrounded by at least one annular gas outlet

Definitions

• the invention relates to a nanoscale nebulizer of a liquid effluent, in a nebulizing gas, and to a nebulization installation comprising such a nebulizer.
• ICPJVIS Inductively Coupled Plasma Torch Mass Spectrometry
• ICP_MS The main benefits of ICP_MS include:
• HCP_MS a potentially attractive technique for the assay of trace compounds in microvolumes of biological samples such as, for example, the contents of individual cells, vacuoles, or "spots", gel spots or bands obtained by gel electrophoresis, after separation by means of chromatography at nanometric rates, less than 500 nl / min for HPLC columns, high performance liquid chromatography, or High Performance Liquid Chromatography in English, with an internal diameter less than or equal to 100 ⁇ m .
• Standard ICP nebulizers currently operate at flow rates of the order of 1 ml / min.
• nebulizers for nebulizing liquid effluents at flow rates of several ⁇ l / min, but none of them allows to nebulize effluent at nanometric rates.
• a nebulizer of this type has been described by the patent application EP 1 081 487. Although designed to provide the nebulization of a liquid effluent over a wide range of flow rates, the minimum flow rate of effluent reached liquid is not less than 5 to 7 ⁇ l / min. Using several elementary streams, the nebulizer mentioned above also uses a supersonic flow gas nebulization gas, which, because of introduced turbulence, does not allow the obtaining of optimum stability of the process and the nebulization flow.
• No. 5,752,663 discloses a nebulizer using a nebulization gas in a laminar flow regime in which the outer side wall of the inner tube is beveled to reduce turbulence in the nebulizing gas and thus obtain the formation of effluent droplets liquid, or aerosol, of similar size, dimension having little dispersion.
• the aforementioned nebulizer does not make it possible to reach a stable nebulization of low flow liquid effluent, less than 1 ⁇ l / min, because of the overall dimensions of the assembly and of the abrupt transition of the outer tube, in the vicinity of the outlet orifice of the liquid effluent, seat turbulence even in laminar regime.
• the object of the invention is to overcome the drawbacks of the prior art liquid effluent nebulizers, in order to allow the implementation of an operational interface allowing the conduct of speciation operations of microbiological or intracellular media, to Liquid effluent flow rates well below 1 ⁇ l / min, in the absence of any dilution.
• Another object of the present invention is, in particular, the implementation of a nanoscale liquid effluent nebulizer for continuously delivering a nebulizer of this effluent over a wide range of flow rates, comprised between ten nanoliters per minute. minute and a thousand nanoliters per minute, under conditions of stability, continuity and outstanding linearity, the upper limit of the flow being able to reach without limitation a few microliters.
• Another object of the present invention is the implementation of a liquid effluent nebulization installation, by successive liquid effluent volume elements, by sampling this effluent, the liquid effluent samples of an elementary volume. of 10 ni or less constituting these volume elements that can be delivered in a repetitive, selective and time-controlled manner, for complex selective speciation operations in the field of biology for example due to the conditions of stability, remarkable continuity and linearity of the aforementioned liquid effluent nebulizer nanometric flow, object of the invention.
• the nanoscale nebulizer of a liquid effluent in a nebulizing gas which is the subject of the invention, is remarkable in that it comprises, at least, disposed substantially of revolution, a capillary tube for admission of this liquid effluent and a Nebulizing needle comprising a central channel supplied with liquid effluent by this capillary tube, an inlet chamber of the nebulizing gas supplying a nozzle for expulsion of this nebulizing gas.
• the nebulization needle passes through the inlet chamber and the expulsion nozzle of the nebulizing gas and comprises an outlet orifice of the liquid effluent whose opening diameter is less than 20 microns.
• the ratio of the diameter of the outlet opening of the expulsion nozzle of the nebulizing gas and the outlet orifice of the liquid effluent of the nebulizing needle is greater than 10.
• the subject of the invention is also a liquid effluent nebulization installation by successive volume elements that is remarkable in that it comprises at least, in cascade, a calibrated flow generator of at least one liquid effluent at a substantially continuous flow rate. less than 1 ⁇ l / min, a controlled valve - AT -
• this nanoscale nebulizer receiving at least one volume element of at least one liquid effluent via a pipe connecting the controlled valve and delivering at least one nebulized liquid effluent volume element.
• the nanoscale nebulizer and the nebulization system find application to mass spectrometry of trace elements contained, for example, in an intracellular or microbiological medium.
• Figure la represents, for illustrative purposes, a sectional view along a longitudinal section plane of symmetry of a nanoscale nebulizer according to the subject of the present invention
• FIG. 1b represents, by way of illustration, a detailed implementation of the connection of the capillary inlet tube of the liquid effluent and of the nebulization needle of the nanoscale nebulizer of the invention shown in FIG.
• FIG. 1C represents, by way of nonlimiting example, a detail of implementation of the outlet orifice of the expulsion nozzle of the nebulizing gas and the nebulizing needle of the nanoscale nebulizer object of the invention shown in Figure la;
• FIG. 2 represents a mounting of a nebulizer and an inductive plasma torch allowing the execution of mass spectrometric analysis of nebulized samples
• FIG. 3 represents, by way of illustration, various curves of intensity of the detected signal in number of strokes per second respectively of the signal stability in% RSD, Relative Standard Deviation in English for relative standard deviation, as a function of the nanoliter flow rate per minute of liquid effluent delivered by a nebulizer nanometer flow object of the invention, for elements such as lithium, yttrium, cesium and thallium, in an assembly as shown in Figure 2;
• FIG. 4 represents, for illustrative purposes, a nebulization installation incorporating a nanoscale nebulizer according to the subject of the invention
• FIG. 5a represents, by way of illustration, liquid effluent detection chronograms containing 600 femtograms of selenium in the form of selenomethionine eluted by 30% of acetonitrile in water in isocratic mode at 300 nl / min and the repetition successive injections of 1 picogram of selenium in the form of selenomethionine contained in 10 ni of this liquid effluent
• FIG. 5b represents, by way of illustration, the detection limit corresponding, by definition, to the concentration of selenomethionine equivalent to a peak whose height or intensity in counts per second is substantially three times greater than the standard deviation of the noise of background ;
• FIG. 5 c represents, by way of illustration, the area of the detection peaks obtained as a function of the nebulized concentration obtained for an isocratic flow rate of liquid effluent H 2 O (70%) / CH 3 CN (30%) fixed at 300 nl / min, injecting 10 ni of a standard of selenomethionine at different concentrations;
• FIG. 5d shows a chromatogram of the intensity of the number of strokes as a function of time in seconds obtained by means of the nebulization installation, object of the invention, coupled to an ICP_MS torch on an analysis sample formed by an elementary volume of 10 nor of a tryptic digestate of selenium protein.
• a nanoscale nebulizer of a liquid effluent in a nebulizing gas will now be described in connection with Figures la to Ic.
• Figures la to Ic In the figure there is shown in section along a longitudinal symmetry section plane a nanoscale nebulizer of a liquid effluent in a nebulization gas according to the subject of the present invention.
• the nebulizer which is the subject of the invention comprises a male part 1 which is intended to be engaged in a female part 2, the male part 1 and the female part being assembled in a sealed manner via O-rings 3.
• the female part 2 comprises an inlet pipe for a nebulizing gas which may for example be constituted by an inert gas such as argon or the like.
• the inlet pipe of the nebulizing gas 4 opens into a fogging gas admission chamber, denoted 4a, the fogging gas inlet chamber comprises a nozzle for expulsion of the nebulizing gas.
• the expulsion nozzle of the nebulizing gas bearing reference 4b is provided with an orifice 4c, a detail of which is shown in FIG.
• the male portion 1 is equipped with a capillary tube 6 maintained for example in position in a bore of the male part 1 by means of a flexible sleeve 7, such as a Teflon sleeve for example.
• a flexible sleeve 7 such as a Teflon sleeve for example.
• the flexible sleeve 7 and finally the capillary tube 6 can then be maintained as shown for illustrative purposes, in Figure la by means of a drilled screw 8 for example.
• the male part 1 comprises, as shown in the above-mentioned figure, a nebulizing needle 9 comprising a central channel 9b illustrated in detail in FIG. 1b and 1c, this central channel being supplied with liquid effluent by the capillary tube 6.
• the inlet chamber of the nebulizing gas 4a feeds the expulsion nozzle of the nebulizing gas 4b.
• the nebulizing needle 9 passes through the inlet chamber 4a and the expulsion nozzle of the nebulizing gas 4b.
• the nebulizing needle comprises an outlet orifice 9a of the liquid effluent whose opening diameter is less than 20 ⁇ m, this diameter being denoted by sur a on the figure Ic.
• the ratio of the diameter ⁇ o of the outlet opening of the expulsion nozzle of the nebulizing gas and the diameter ⁇ a of the outlet orifice of the nebulizing needle is advantageously greater than 10 is 10 ⁇ o / ⁇ a .
• the specific arrangement of the nanoscale nebulizer of a liquid effluent in a nebulizing gas, object of the present invention allows to create the conditions of optimal flow of the nebulizing gas beyond the outlet 4c of the expulsion nozzle of the nebulizing gas and to cause an optimal contact between the liquid effluent delivered by the orifice ⁇ a of the nebulizing needle 9 as will be described hereinafter with reference to FIG.
• outlet orifice 4c of the expulsion nozzle of the nebulizing gas and the end of the nebulizing needle 9 form a Venturi profile nozzle operating substantially in a steady state. subsonic flow.
• the end of the nebulizing needle 9 with the outlet diameter of the liquid effluent orifice ⁇ has passes through the gas ejection nozzle nebulization 4b and is placed au beyond the zone of maximum speed of expulsion of the gas, in the flow direction of the nebulizing gas.
• the channel 9b of the needle 9 may advantageously have a decreasing diameter towards the end bearing the outlet orifice, to accelerate the ejection speed of the effluent, without, however, unacceptably increasing the pressure and the losses. upstream loads.
• the zone of maximum expulsion speed of the gas is situated substantially at the level of the maximum strangulation of the gas expulsion nozzle 4b and in particular at the level of the zone of aperture corresponding to the opening diameter ⁇ o previously described and shown in Figure Ic.
• the relative arrangement of the nebulizing needle 9 and in particular of the opening opening of the channel 9b of the latter beyond the maximum expulsion zone of the nebulization gas, as shown in FIG. allows the liquid effluent to be delivered into the central zone of the nebulizing gas flow substantially in the absence of turbulence and in a substantially laminar flow zone.
• the interaction between the liquid effluent delivered in the aforementioned laminar flow of the evolved nebulization gas flow allows a physical interaction between the liquid effluent and the nebulizing gas causing the creation of a nebulizer, c that is, a dispersion of the liquid effluent in very fine droplets.
• the capillary tube 6 and the nebulizing needle 9 are aligned and centered on the longitudinal axis of symmetry of the nebulizer materialized in Figure la by the capillary tube 6 and the nebulizing needle 9.
• the central channel 6a of the capillary tube 6 as shown in FIG. 1b and the central channel 9b of the nebulizing needle 9 are furthermore aligned and have the same diameter at least equal to twice the diameter of the opening of the outlet orifice 9a of the nebulizing needle 9.
• the capillary tube 6 and the nebulizing needle 9 are mounted in the male portion 1 substantially symmetrical with respect to the longitudinal axis of the nebulizer.
• the male part has for this purpose, a longitudinal bore la provided with a radial seat Ib allowing the supporting and maintaining the capillary tube 6 and the nebulizing needle 9.
• the radial seat Ib has a central opening Ic allowing the engagement of the capillary tube 6 and the nebulizing needle 9 and the abutment of the central channel of these.
• the capillary tube 6 may advantageously be a fused silica capillary tube, the capillary 6 being then held in the male part 1 of the nebulizer and in particular in the bore 1a of the latter by means of the flexible sleeve 7 such as a sleeve Teflon for example and the pierced screw 8, which may advantageously be made of a plastic material such as polyetheretherketone fiber still referred to as PEEK.
• the nebulizing needle 9 is preferably made of the same material as the capillary tube 6 and in particular fused silica.
• the aforementioned needle can then be of the same type as that used in the context of the "nanoelectrospray" technology in ESIJVIS.
• the nebulizing needle 9 may advantageously also be held in position in the bore 1a of the male part 1 by means of a sleeve 10 of flexible material such as Teflon and by means of a PEEK drilled screw. represented in the drawing.
• this hole may consist of a hole 600 microns long and 300 microns in diameter, for example, drilled in the aforementioned radial seat.
• the outlet orifice 4c of the nebulizing expulsion nozzle 4b is formed and comprises a crown of machining material with a high tolerance, this ring bearing the reference 11.
• the outlet orifice of the nebulizing gas may, by way of non-limiting example, be formed by an industrial sapphire ring through which the nebulizing needle is introduced.
• the diameter of the outlet orifice of the nozzle for expelling the nebulizing gas, diameter ⁇ o can then be taken to be equal, in a ratio of 26 to 260 ⁇ m.
• the nebulizing needle is positioned in the center of the flow, particularly as regards the outlet orifice of the latter.
• the distal end of the nebulizing needle and in particular the external wall thereof has a bevelled profile to form with the flared wall of the expulsion orifice of the nebulization gas the Venturi nozzle mentioned previously in FIG. the description.
• the angle of inclination of the bevelled wall in the plane of FIG. 1c relative to the longitudinal axis of the nebulizing needle 9 and the central channel 9b thereof can then be taken to be equal to a value between 10 and 30 degrees.
• FIG. 2 shows a mounting of a nebulizer and an inductive plasma torch allowing the execution of mass spectrometric analysis of nebulized samples.
• A denotes a nebulizer according to the subject of the present invention as described above in connection with Figures 1a to Ic and B advantageously designates a removable nebulization chamber, which can be detached from the nebuliser A itself but constitutes an integral part of it, under the following conditions.
• the nebulizing chamber B is reduced in order to to minimize the dead volumes which have a considerable influence on the reaction time of all the devices in the case of transient signals.
• the nebulizing chamber can be removable and is then sealingly connected to the female part 2 of the nebulizer shown in FIG. 1a, the sealing during assembly being ensured by means of the O-rings 5 shown in FIG. 5a above.
• the nebulizing chamber comprises a nebulization space formed for example by a Pyrex glass tube further comprising a tapered tube for connecting the nebulization space and a plasma torch in which the plasma is created to perform the analysis by mass spectrometry.
• the plasma torch carries the reference C in FIG.
• FIG. 3 Various indications and test reports will now be given in connection with FIG. 3 for a nanoscale nebulizer according to the subject of the present invention previously described in connection with FIG. 1a, 1b and 1c, installed in an assembly such as as shown in Figure 2.
• the nebulizer which is the subject of the invention, was tested for a flow rate range of between 50 nl / min and 450 nl / min with a nebulization gas flow rate consisting of argon at a flow rate of 1.1 min.
• the liquid effluent nebulization installation which is the subject of the invention, is remarkable in that it comprises at least in cascade a calibrated flow generator G of at least one effluent liquid at a substantially continuous flow rate less than 1 .mu.l / min and a controlled valve V receiving the calibrated flow of liquid effluent and for delivering by temporal sampling control of this calibrated stream at least one volume element of this liquid effluent.
• a nebulizer with nanoscale flow A is connected to the controlled valve V and receives at least one volume element of at least one liquid effluent via a connecting pipe to the controlled valve and delivers at least one volume element of nebulized liquid effluent.
• Each liquid effluent volume element is integrated with a concentration gradient in the continuous flow of eluent.
• the calibrated flow generator G of at least one liquid effluent comprises at least one high-pressure pump P that is selectively fed by a plurality of separate liquid effluents, the high-pressure pump pressure delivering a substantially continuous flow at high pressure and at a given flow rate of one of the liquid effluents.
• the pump P can be connected to a plurality of effluent tanks T 1 and T 2 , each effluent can be selected selectively.
• the generator G may comprise a liquid effluent flow reducer R enabling a reduced flow to flow from the substantially continuous flow delivered by the pump P in a given flow ratio of the liquid effluent.
• the liquid effluent flow reducer was a flow reducer to bring the flow rate of 100 ⁇ l / min. mentioned above at the value of 0.3 ⁇ l / min.
• a flow calibrator C then makes it possible to deliver from the reduced flow of the liquid effluent a calibrated flow of liquid effluent whose flow rate does not exceed 0.5 ⁇ l / min.
• the flow calibrator C is not essential for lower flows.
• each liquid effluent volume element may advantageously represent a volume of 10 nl.
• the use of the aforementioned controlled valve and a liquid chromatography column of 75 ⁇ m internal diameter, the aforementioned column for connecting the controlled valve V nebulizer A then allows to use and characterize the nebulizer to Nanometric flow object of the invention, in the case of a regime and a transient signal.
• This transient signal can result from the detection of a volume element transmitted by the controlled valve V.
• FIGS. 5a to 5d make it possible, in particular, to highlight the signals detected in the form of peaks represented in FIG. 5a in particular.
• FIG. 5a represents the detected signal in the form of a peak profile corresponding to 600 femtograms of selenium in the form of selenomethionine eluted by 30% of acetonitrile in water in isocratic mode with a flow of nebulisate of 300 nl / min. and the reproduction of 1 picogram injections of such a liquid effluent, by means of a nebulization installation as represented in FIG. 4.
• the peaks obtained represented in FIG. 5a are substantially symmetrical, these peaks being represented in intensity of strokes per second c / s on the ordinate axis, respectively in time in second on the abscissa axis and have a typical Gaussian profile.
• the reproducibility of the analysis can be characterized by the relative difference in the areas of the peaks of a series of successive injections of the same sample as represented in the same figure 5a. With reference to the aforementioned figure, this difference does not exceed 5% despite a background noise of the signal having a relative standard deviation of 3.5%.
• FIG. 5b makes it possible to evaluate the sensitivity limit for the selenium of a nebulization installation as represented in FIG. 4.
• the limit of detection sensitivity corresponds, by definition, to the concentration equivalent to a detection peak whose height would be three times, for example, the standard deviation of the background noise, as represented in FIG. 5b.
• the ordinate axis is graduated in intensity I of the signal detected in counts per second c / s and the abscissa in selenium concentration in nanograms per gram.
• the curve shown in FIG. 5c was obtained for an isometric flow rate H 2 O (70%) / CH 3 CN (30%) set at 300 rpm, by injecting 10 ⁇ l of a selenomethionine standard at different concentrations. It is indicated that the volume of 10 ni above corresponds to a volume element of liquid effluent injected through the installation implemented in accordance with the installation object of the invention shown in FIG. 4.
• R 2 0.9994 exhibiting a linearity defect as low as 6 ⁇ 10 -4 demonstrates the particularly remarkable linearity of the response of the nebulization installation according to the subject of the present invention, as represented in FIG. 4 and the precision which makes it follows.
• FIG. 5d represents a chromatogram making it possible to test the actual results on a real sample of 10 ⁇ l of a tryptic digestate of selenium protein, analyzed by means of a nebulization installation, as represented in FIG. 4, coupled to an inductive plasma torch of mass spectrometry.
• the gradient of acetonitrile in the water used was as follows:
• the procedure for carrying out the analysis of the selenium protein digestate shown in FIG. 5d is obtained by implementing a method for analyzing trace elements in a sample.
• method of liquid effluent analysis by inductively coupled plasma torch mass spectrometry particularly remarkable in that it consists in generating from a continuous flow of liquid effluent a nebulisate of liquid effluent to be analyzed at a flow rate between 10 nl / min and 600 nl / min then to introduce the nebulisat constituting the analysis sample in an inductively coupled plasma torch to perform the mass spectrometric analysis of the aforementioned analysis sample.
• the method consists in sampling the continuous flow of liquid effluents by liquid effluent volume elements of volume substantially equal to 10. or.
• the nebulizer with a nanometric flow rate of a nebulization installation comprising such a nebulizer and the analysis method according to the subject of the present invention make it possible to obtain a better resolution, a saving of samples and of eluent due to the decrease. dimensions of the entire nebulization installation as well as a very significant decrease in the analysis time due to the introduction of sub-microliter nebulisate flow rate per minute into the inductive plasma torch.

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• 2005
  • 2005-06-09 FR FR0505884A patent/FR2886871B1/fr not_active Expired - Fee Related
• 2006
  • 2006-06-01 WO PCT/FR2006/001249 patent/WO2006131626A2/fr not_active Ceased
  • 2006-06-01 EP EP06764717A patent/EP1888250A2/de not_active Withdrawn
  • 2006-06-01 US US11/916,396 patent/US7863560B2/en not_active Expired - Fee Related

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