RU2733530C1 - Apparatus for depositing nanoparticles of metal oxides on a metal surface under normal conditions - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to mass spectrometry and will find wide application in solving analytical problems of organic and bioorganic chemistry, immunology, biotechnology, forensics, proteomics, metabolomics and medicine, metabonomics and post-translational modification. Device for depositing nanoparticles of metal oxides on a metal surface under normal conditions is made in the form of coaxially arranged capillaries oriented vertically. Solution is supplied through the internal metal capillary, (suspension of nanoparticles) to the same capillary voltage is applied from the high-voltage power supply source. At end of said capillary there is drip-free electric spraying of nanoparticles under normal conditions. Coaxial external capillary has inner diameter larger than outer diameter of internal capillary. Surpluses of non-sprayed solution, which moisten the external wall of the internal capillary, together with laboratory air are pumped by an air pump through a gap between coaxial capillaries.

EFFECT: metal surface of MALDI target is at room temperature, solvent vapors are effectively removed from nanoparticles application area on target, spots of nanoparticles on targets of required sizes are obtained without application of stencils and their boundaries are strictly limited, diameter of capillary on which solution is supplied, which allows to use nanoparticles with wide distribution on sizes; absence of microdroplets of solution during spraying allows to obtain mechanically resistant to abrasion coatings of deposited metal oxides, which will enable to carry out multiple experiments with target.

1 cl, 5 dwg

Description

The present alleged invention relates to the field of mass spectrometry, namely to devices for applying nanoparticles of metal oxides to a metal surface under normal conditions during sample preparation of biological samples and environmental objects for their analysis using soft ionization methods - ESI (electrospray) [1, 2 ] and MALDI (matrix-activated laser desorption / ionization) [3] and will find wide application in solving analytical problems in organic and bioorganic chemistry, immunology, medicine, diagnosis of diseases, biochemical research, pharmaceuticals, analyzes in proteomics, metabolomics for phosphoproteomics and adductomics, trace analysis of biochemical markers.

Analysis of biological samples requires a sensitive detection method and careful sample preparation, as the sample is a complex matrix and the analyte is usually present in low concentrations. One of the specific and selective methods used for the preparation of biological samples is metal-affinity chromatography. Sorbents used in this method consist of nanoparticles of oxides of various metals. As is known, transition metal ions can interact with various functional groups of organic and bioorganic molecules with different efficiency [4].

Metal affinity chromatography is carried out in microcolumns of various formats filled with a sorbent, then the separated fractions are analyzed by instrumental methods. For example, high performance liquid chromatography or mass spectrometry methods are used.

The sample preparation of some samples is carried out directly on the surface of a steel target for MALDI mass spectrometry and, first of all, the affinity concentration of analytes for the purposes of phosphoproteomics and adductomics.

Known device for applying nanoparticles of metal oxides to a metal surface [5] for preliminary concentration of the analyte on the surface of a steel target. The considered device is a set of parts and devices necessary for the deposition of nanoparticles of metal oxides on a metal surface. The device includes: a mill for grinding nanoparticles, an ultrasonic bath, a high-temperature furnace (400 ° C), a stencil with the help of which prints of specially prepared ink containing nanoparticles of metal oxides are applied localized on a metal surface.

The disadvantage of the known device when using the listed parts and devices included in its composition is the long time of more than 12 hours to obtain a stable coating of metal oxides on a metal substrate. In addition, during annealing, toxic solvent vapors are released and there is a risk of thermal burns at high temperatures of the metal substrate.

The known device [6] for applying nanoparticles of metal oxides to a metal surface is a set of devices and parts consisting of: an ultrasonic bath, a plasma reactor with reduced oxygen pressure, a high-voltage power supply, a metal capillary, a syringe liquid pump, a target, a heater with temperature control up to 200 ° C.

The disadvantage of the known device is the drop in a wide range of sizes electrospray of a solution (suspension) of nanoparticles, heating the target to 200 ° C in order to evaporate droplets with nanoparticles before their deposition on the target. Impossibility of simultaneous treatment of the target surface with oxygen plasma in order to clean it and deposit metal oxide nanoparticles using electrospray of a solution (suspension).

The closest known technical solution for a similar purpose selected as a prototype is an ion source device with electrospray solutions to obtain a drip-free stable flow of charged particles for a long time [7], containing an electrospray solution, consisting of a central metal capillary, and an external capillary coaxial to it, forming a coaxial channel, a central metal capillary electrically connected to a regulated high-voltage voltage source, a counter electrode, a coaxial external capillary made of dielectric, a coaxial channel connected to a dehumidifier, behind which a gas flow meter is located connected to a controlled air micropump, and a metal capillary is connected to an injector, input which is connected to the solution supply device, perpendicular

The nebulizer axis is equipped with an optical magnifying system, the focus of which is at the top of the solution meniscus at the end of the metal capillary, and a video camera is located on the eyepiece of the optical magnifying system, the image from which is fed to the display system (tablet).

The disadvantage of the known device is the pumping of a non-atomized suspension (a vapor-gas mixture - water, acetonitrile and nanoparticles) through a coaxial channel into a separate non-insulated container, which complicates the maintenance of the device during operation due to acetonitrile vapors, as well as the small inner diameter of the metal capillary (100 μm) with a wide spread of nanoparticle sizes in the solution, which leads to clogging of the capillary and interruption of the nanoparticle deposition process.

The purpose of the proposed device is to eliminate the above-described disadvantages, the formation of a spot of deposited nanoparticles on the surface of a metal target without heating with a diameter of no more than 5 mm, which corresponds to a hole on the target mass spectrometry used in MALDI without the use of masks and stencils, the mechanical strength of the sprayed layer of nanoparticles for carrying out with it manipulations during preliminary concentration of the bioorganic sample. Pre-preparation of the surface to be sprayed is subjected to a single rinsing with a solvent. During the deposition process, the target surface remains dry.

These problems are solved due to the fact that the known device containing an electrospray of solutions, consisting of a central metal capillary, and an external capillary coaxial to it made of a dielectric, forming a coaxial channel, a central metal capillary electrically connected to a regulated source of high-voltage voltage, a counter electrode - a MALDI target, the coaxial channel is connected to a dehumidifier, behind which there is a controlled air micropump, and a central metal capillary is connected to a solution supply device, an optical magnifying system is located perpendicular to the atomizer axis, the focus of which is at the top of the solution meniscus at the end.

The inventive device for applying nanoparticles of metal oxides to a metal surface under normal conditions is schematically shown in figure 1. A solution (suspension) is fed through an internal metal capillary (1) from a solution feeding device (2). Voltage is applied to the same capillary from a high-voltage power source (3). The end of the capillary (1), from which electrospray occurs, is oriented vertically downward. Coaxial to the capillary (1) is an external dielectric capillary (4) with an inner diameter larger than the outer diameter of the capillary (1). Excess unsprayed solution, wetting the outer wall of the capillary (1), together with laboratory air, are pumped out by an air pump (5) through the gap between the coaxial capillaries (1) and (4). A filtration system (6) is installed in front of the pump to separate air from solvents. Opposite the end of the inner capillary (1) in the horizontal plane is a flat counter electrode (MALDI target) (7), which is electrically connected to the ground. For visual observation of the meniscus and the desorption process, a microscope (8) with a digital video camera located on it (9) is used. The image from the video camera goes to the computer (10). To illuminate directly the area of the solution meniscus and the area of the counter electrode, on which the deposition is performed, an LED unit (11) with a power source (12) is used. Figure 2 shows a photo of the meniscus shape in the drip-free electrospray solution. Figure 3 shows a photo of a spot of nanoparticles based on iron (III) oxide on a substrate during electrospray of a suspension in a drip-free mode with dynamic flow division. Spot diameter ~ 4 mm. Figure 4 shows a photo of a fragment of a MALDI target, the surface of which has been modified with nanoparticles based on iron (III) oxide by drip-free electrospray, and figure 5 shows a micrograph of the surface of a steel plate, the surface of which has been modified with nanoparticles based on iron (III) oxide.

Sources of information

1. Alexandrov M.L., Gal L.N., Krasnov N.V., Nikolaev V.I., Pavlenko V.A., Shkurov V.A. Extraction of ions from solutions at atmospheric pressure is a new method of mass spectrometric analysis. DAN SSSR T. 277, No. 2. Physical chemistry, 1984, pp. 379-383.

2.M. Yamashita, J.B. Fenn Electrospray ion source. Another variation on the free-jet theme J. Phys. Chem. 1984. V.88, N20, P. 4451-4459. DOI 10.1021 / j150664a002.

3. Karas, M .; Bachmann, D .; Bahr, U .; Hillenkamp, F., Matrix-Assisted Ultraviolet-Laser Desorption of Nonvolatile Compounds. Int. J. Mass Spectrom. Ion Processes 1987, V. 78, P. 53-68. Doi.org/10,1016/0168-1176(87) 87041-6.

4. Keltsieva O.A., Gladilovich V.D., Podolskaya E.P. Metal affinity chromatography. Fundamentals and Application // Scientific Instrument Engineering. 2013. T. 23, No. 1. S. 74-85. URL: http://iairas.ru/mag/2013/abst1.php#abst9.

5. Hongyan Bi, Liang Qiao, Jean-Marc Busnel, Valerie Devaud, Baohong Liu, and Hubert H. Girault. TiO ₂ Printed Aluminum Foil: Single-Use Film for a Laser Desorption / Ionization Target Plate. J. American Chemical Society. 2009, V.81, N3, P. 1177-1183. DOI: 10.1021 / ac8024448.

6. Grady R. Blacken, Michael Volny, Matthew Diener, Karl E. Jackson, Pratistha Ranjitkar, Dustin J. Maly, and Frantisek Turecek. Reactive Landing of Gas-Phase Ions as Tool for the Fabrication of Metal Oxide Surfaces for In Situ Phosphopeptide Enrichment. J. American Society for Mass Spectrometry. 2009, No. 20, P. 915-926. DOI: 10.1016 / j.jasms.2009.01.006.

7. RF patent No. 169146 priority 09.12.2015. "The device of the ion source - electrospray to obtain a drop-free stable ionic current of the analyzed substances from solutions for a long time." Krasnov N.V., Krasnov M.N.

Claims (1)

A device for applying metal oxide nanoparticles from solutions by electrospray in a drip-free mode on a metal surface under normal conditions, containing an electrospray of solutions, consisting of a central metal capillary and an external capillary coaxial to it, forming a coaxial channel, a central metal capillary electrically connected to a regulated source of high voltage , the coaxial external capillary is made of a dielectric, the coaxial channel is connected to a dehumidifier, behind which a gas flow meter, a controlled air micropump are located in series, and a metal capillary is connected to an injector, the inlet of which is connected to an eluent supply device, an optical magnifying system is located perpendicular to the atomizer axis, focus which is located at the top of the meniscus of the liquid at the end of the metal capillary, and a video camera is located on the eyepiece of the optical magnifying system, characterized in that the diameter tr of the central metal capillary is not less than 0.4 mm, the distance from the top of the liquid meniscus to the metal surface is 10 mm, the free end of the coaxial outer capillary is made in the form of a cone, and the metal surface of the target is the counter electrode.

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