Mass spectrometery calibrant liquid container level sensing

Patent metadata

Field	Value
Publication number	US-2023134726-A1
Application number	US-202117519416-A
Country	US
Kind code	A1
Filing date	Nov 4, 2021
Priority date	Nov 4, 2021
Publication date	May 4, 2023
Grant date	—

Abstract

Determining a level of a liquid in a container is described. In one aspect, a container includes a calibrant liquid used for calibrating a mass spectrometer. A conductive layer is placed to float upon the calibrant liquid, and a circuit board with electrodes is arranged around the container. A controller circuit then drives and measures various electrodes to first identify which two electrodes the level of the calibrant liquid is between, and then subsequently identify a more precise location for the level between the two electrodes.

First claim

I/We claim:

1 . A method of calibrating a mass spectrometer, comprising:
applying first signals having a first phase to a first measure electrode and a second measure electrode, the first and second measure electrodes arranged around a container holding a calibrant liquid and a conductive layer floating upon the calibrant liquid, the conductive layer capacitively coupled with the first and second measure electrodes, and a density of the conductive layer being lower than a density of the calibrant liquid; applying second signals having a second phase different than the first phase to the first and second measure electrodes; determining that a monitor signal from a monitor electrode capacitively coupled with the conductive floating layer has changed from the first phase to the second phase upon application of the second signal to the second measure electrode; identifying the first measure electrode being above a level of the calibrant liquid, and the second measure electrode being below the level of the calibrant liquid upon the determination that the monitor signal has changed from the first phase to the second phase; applying a third signal having the first phase to the first measure electrode, and a fourth signal having the second phase to the second measure electrode; identifying the level of the calibrant liquid between the first measure electrode and the second measure electrode by differentially adjusting an amplitude of the third signal and an amplitude of the fourth signal until a phase of the monitor signal oscillates between the first phase and the second phase; and generating a calibration mass spectrum indicative of components of the calibrant liquid to facilitate calibration of the mass spectrometer; and calibrating the mass spectrometer based on the calibration mass spectrum.

2 . The method of claim 1 , wherein the conductive layer includes conductive beads.

3 . The method of claim 2 , wherein the conductive beads include gold-shelled polystyrene particles.

4 . The method of claim 1 , wherein the first phase and the second phase are approximately 180 degrees out of phase with each other.

5 . The method of claim 1 , wherein the amplitude of the third signal is decreased, and the amplitude of the fourth signal is increased when differentially adjusting the amplitudes.

6 . The method of claim 1 , wherein the level of the calibrant liquid between the first measure electrode and the second measure electrode is an inverse of a ratio of the amplitudes.

7 . An apparatus for determining a level of a liquid in a container, comprising:
a container having a conductive layer floating upon a liquid; a circuit board disposed around the container, and having measure electrodes and a monitor electrode arranged around the container; and a controller circuit configured to drive the measure electrodes and measure a monitor signal provided by the monitor electrode to identify a first electrode and a second electrode that a level of the liquid is in between, and further identify a location between the first electrode and the second electrode that the level of the liquid is at.

8 . The apparatus of claim 7 , wherein identifying the first electrode and the second electrode that the level of the liquid is in between includes determining the monitor signal switched from a first phase to a second phase when a signal applied to the second electrode switches from the first phase to the second phase, the second electrode being below the level of the liquid, and the first electrode being above the level of the liquid.

9 . The apparatus of claim 7 , wherein identifying the location between the first electrode and the second electrode that the level of the liquid is at includes adjusting an amplitude a signal applied to the first electrode and an amplitude of a signal applied to the second electrode until a phase of the monitor signal oscillates between the first phase and the second phase.

10 . The apparatus of claim 9 , wherein the amplitude of the signal applied to the first electrode is decreased, and the amplitude of the signal is increased when adjusting the amplitudes.

11 . The apparatus of claim 7 , wherein the conductive layer includes conductive beads.

12 . The apparatus of claim 11 , wherein the conductive beads include gold-shelled polystyrene particles.

13 . The apparatus of claim 11 , wherein the liquid is a calibrant liquid for calibrating a mass spectrometer.

14 . An apparatus for determining a level of a liquid in a container, comprising
a circuit board configured to wrap around a container having a conductive layer floating upon a liquid, and configured to have electrodes disposed around the container; and a controller circuit configured to drive the electrodes and identify a first electrode and a second electrode that a level of the liquid is in between, and further identify a location between the first electrode and the second electrode that the level of the liquid is at after identifying the first electrode and the second electrode.

15 . The apparatus of claim 14 , wherein identifying the first electrode and the second electrode that the level of the liquid is in between includes determining a signal at an electrode that is capacitively coupled to the conductive layer has switched from a first phase to a second phase when a signal applied to the second electrode switches from the first phase to the second phase, the second electrode being below the level of the liquid, and the first electrode being above the level of the liquid.

16 . The apparatus of claim 14 , wherein identifying the location between the first electrode and the second electrode that the level of the liquid is at includes adjusting an amplitude a signal applied to the first electrode and an amplitude of a signal applied to the second electrode until a phase of a monitor signal oscillates between the first phase and the second phase.

17 . The apparatus of claim 16 , wherein the amplitude of the signal applied to the first electrode is decreased, and the amplitude of the signal is increased when adjusting the amplitudes.

18 . The apparatus of claim 14 , wherein the conductive layer includes conductive beads.

19 . The apparatus of claim 18 , wherein the conductive beads include gold-shelled polystyrene particles.

20 . The apparatus of claim 18 , wherein the liquid is a calibrant liquid for calibrating a mass spectrometer.

Assignees

• Thermo Finnigan Llc

Inventors

• Mathur Raman
• Le Thi
• Minkler David E

Classifications

• H01J49/0431

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

• H01J49/0009 Primary

  Calibration of the apparatus · CPC title

• G01N30/7233 Primary

  interfaced to liquid or supercritical fluid chromatograph (interfaces in general for introducing or extracting samples to be analysed with specially adapted mass spectrometer, see H01J49/04) · CPC title

• G01N30/8665

  for calibrating the measuring apparatus · CPC title

• G01F23/76

  characterised by the construction of the float · CPC title