System and method for liquid extraction electrospray-assisted sample transfer to solution for chemical analysis

Patent metadata

Field	Value
Publication number	US-2016126080-A1
Application number	US-201414529307-A
Country	US
Kind code	A1
Filing date	Oct 31, 2014
Priority date	Oct 31, 2014
Publication date	May 5, 2016
Grant date	—

Abstract

A system for sampling a surface includes a surface sampling probe comprising a solvent liquid supply conduit and a distal end, and a sample collector for suspending a sample collection liquid adjacent to the distal end of the probe. A first electrode provides a first voltage to solvent liquid at the distal end of the probe. The first voltage produces a field sufficient to generate electrospray plume at the distal end of the probe. A second electrode provides a second voltage and is positioned to produce a plume-directing field sufficient to direct the electrospray droplets and ions to the suspended sample collection liquid. The second voltage is less than the first voltage in absolute value. A voltage supply system supplies the voltages to the first electrode and the second electrode. The first electrode can apply the first voltage directly to the solvent liquid. A method for sampling for a surface is also disclosed.

First claim

1 . A system for sampling a surface, comprising:
a surface sampling probe comprising a solvent liquid supply conduit and a distal end; a sample collector for suspending a sample collection liquid adjacent to the distal end of the surface sampling probe; a first electrode for providing a first voltage to solvent liquid at the distal end of the surface sampling probe, the first voltage producing a field sufficient to generate an electrospray at the distal end of the surface sampling probe; a second electrode for providing a second voltage, the second electrode being positioned to produce an electrospray plume directing field sufficient to direct electrosprayed droplets and ions at the distal end of the surface sampling probe to the suspended sample collection liquid, the second voltage being less than the first voltage in absolute value; and a voltage supply system for supplying the voltages to the first electrode and the second electrode.

2 . The system of claim 1 , further comprising a driver for moving the distal end of the surface sampling probe between at least a surface-adjacent position and a surface-remote position.

3 . The system of claim 2 , wherein the voltage system supplies an electrospray generating voltage to the first electrode when the surface sampling probe is in the surface-remote position, and for supplying a non-electrospray generating voltage difference when the surface sampling probe is in the surface-adjacent position.

4 . The system of claim 2 , wherein the driver oscillates the distal end of the surface sampling probe between the surface-adjacent position and the surface-remote position at between 1 Hz and 100 MHz.

5 . The system of claim 1 , wherein the second electrode is electrically connected to the sample collector.

6 . The system of claim 1 , wherein the second electrode is positioned such that the second voltage is applied to the sample collection liquid.

7 . The system of claim 1 , wherein the second electrode comprises a plume-directing structure for directing the movement of the charged droplets and ions toward the sample collector.

8 . The system of claim 2 , wherein the second electrode is a plate and the plume-directing structure is an opening in the plate, and wherein the plate and the plume-directing opening are interposed between and not connected to the sample collector and the distal end of the probe when the probe is in the surface-remote position.

9 . The system of claim 1 , wherein the first electrode applies the first voltage directly to the solvent liquid.

10 . The system of claim 1 , further comprising at least a third electrode for providing a third voltage, the third electrode being positioned remotely to the second electrode, the third voltage producing a plume-directing field that is supplemental to the plume-directing field of the second electrode.

11 . The system of claim 10 , wherein the second electrode is located remotely to the sample collector and positioned at a distance from the distal end of the surface sampling probe, and the third electrode is positioned at greater distance to the distal end of the surface sampling probe.

12 . The system of claim 11 , wherein a fourth electrode is connected to the sample collector, and a plume-directing voltage is applied to the fourth electrode.

13 . The system of claim 1 , wherein the surface sampling probe comprises a probe body having a liquid inlet and a liquid outlet, and having a liquid extraction tip, a solvent delivery conduit for receiving solvent liquid from the liquid inlet and delivering the solvent liquid to the liquid extraction tip, and an open liquid extraction channel extending across an exterior surface of the probe body from the liquid extraction tip to the liquid outlet; and an electrospray emitter tip in liquid communication with the liquid outlet of the liquid extraction surface sampling probe.

14 . The system of claim 1 , wherein the electrospray-generating field is at least 10 8 V/m.

15 . The system of claim 1 , wherein the field at the distal end of the surface sampling probe is at least 10 8 V/m.

16 . The system of claim 2 , wherein the surface adjacent position is less than 1 mm from the sample surface.

17 . The system of claim 2 , wherein the surface-remote position is between 1 μm and 5 cm from the sample surface.

18 . The system of claim 2 , wherein the driver comprises a mechanical relay.

19 . The system of claim 2 , wherein the driver comprises a piezoelectric device.

20 . The system of claim 2 , wherein the driver comprises an atomic force microscopy cantilever system.

21 . The system of claim 1 , further comprising a pump for pumping solvent through the solvent liquid supply conduit to the surface, and for withdrawing solvent from the surface through the conduit.

22 . The system of claim 1 , wherein the sample collection liquid is suspended statically.

23 . The system of claim 1 , wherein the sample collection liquid is suspended dynamically.

24 . The system of claim 23 , wherein the sample collector comprises:
a sample collection liquid suspension opening; a sample collection liquid supply conduit communicating with the suspension opening; and a sample collection liquid removal conduit communicating with the suspension opening, wherein the sample collection liquid suspension opening, the sample collection liquid supply conduit, and the sample collection liquid removal conduit are sized to allow a rate of supply of collection liquid to be balanced with a rate of removal such that the sample collection liquid passes the suspension opening to receive charged droplets and ions from the surface sampling probe but does not exit the probe through the suspension opening and is removed through the removal conduit.

25 . The system of claim 1 , further comprising at least one separation device for separating samples in the sample collection liquid.

26 . The system of claim 25 , wherein the separation device comprises at least one selected from the group consisting of liquid chromatography, solid phase extraction, high pressure liquid chromatography (HPLC), ultra pressure liquid chromatography (UPLC), capillary electrophoresis, ion mobility spectrometry and differential mobility spectrometry.

27 . The system of claim 1 , further comprising a mass spectrometer for analyzing samples from the sample collection liquid, the mass spectrometer being at least one selected from the group consisting of sector MS, time-of-flight MS, quadrupole mass filter MS, three-dimensional quadrupole ion trap MS, linear quadrupole ion trap MS, Fourier transform ion cyclotron resonance MS, orbitrap MS, and toroidal ion trap MS.

28 . A method for analyzing a surface, comprising the steps of:
providing a surface sampling probe comprising a solvent liquid supply conduit and a distal end; positioning a sample collector for suspending a sample collection liquid adjacent to the distal end of the surface sampling probe; applying a first voltage to the distal end of the surface sampling probe, the first voltage producing a field sufficient to generate an electrospray at the distal end of the surface sampling probe; applying a second voltage to an electrode positioned such that electrospray plume generated at the distal end of the surface sampling probe is directed to the suspended sample collection liquid, a second absolute va

Assignees

• Ut Battelle Llc

Inventors

• Kertesz Vilmos
• Van Berkel Gary J

Classifications

• H01J49/142 Primary

  using a solid target which is not previously vapourised · CPC title

• H01J49/0431

  for liquid samples (interfaces to liquid chromatographs G01N30/7233) · CPC title

• H01J49/167 Primary

  Capillaries and nozzles specially adapted therefor; (electrostatic spraying per se B05B5/00) · CPC title

• H01J49/04

  Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components · CPC title

• H01J49/26

  Mass spectrometers or separator tubes · CPC title