Analytical system and method for detecting volatile organic compounds in water

• US 10,161,920 B2
• Filed: 09/18/2017
• Issued: 12/25/2018
• Est. Priority Date: 09/07/2011
• Status: Active Grant

• Current Assignee: Parker Intangibles LLC (Parker-Hannifin Corporation)
• Original Assignee: Parker-Hannifin Corporation
• Inventors: Hassan, Kazi Z. A., Cost, William M., Morse, John Arthur, Doutt, Michael L., Geis, Glenn Stacey
• Primary Examiner(s): West, Paul M.
• Assistant Examiner(s): Shabman, Mark A
• Application Number:
  US15/707,381
• Publication Number:
  US 20180003682A1
• Time in Patent Office: 463 Days
• Field of Search: None
• CPC Class Codes: G01N 1/10 in the liquid or fluent state burettes, pipettes B01L3/02; sampling of ground water E02D1/06; metering by volume of fluids or fluent solid material G01F11/00, G01F13/00
• CPC Class Codes: G01N 1/4055 by solubility techniques
• CPC Class Codes: G01N 2001/4066 using difference of solubility between liquid and gas, e.g. bubbling, scrubbing or sparging
• CPC Class Codes: G01N 2030/025 Gas chromatography
• CPC Class Codes: G01N 2291/021 Gases
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 30/76 Acoustical detectors measurement of mechanical vibrations or ultrasonic, sonic or infrasonic waves G01H

Abstract

An analytical system and method for detecting volatile organic chemicals in water including a coated SAW detector that provides for improved reduction of moisture at the coating of the SAW detector. A stabilized SAW sensitivity and long lasting calibration is achieved. The analytical system further includes an improved sample vessel and sparger that allow for easy grab sample analysis, while also providing efficient purging of the volatile organic compounds from the water sample. In addition, an improved preconcentrator provides a stabilized sorbent bed.

Claims

1. A system for detecting organic compounds in water including:

a preconcentrator configured to collect the organic compounds;

a gas chromatograph column configured to separate the organic compounds as desorbed from the preconcentrator;

a surface acoustic wave detector configured to detect the mass of the organic compounds separated by the gas chromatograph;

a housing that houses the preconcentrator, the gas chromatograph column, and the surface acoustic wave detector;

a sample vessel removably attached to the housing and configured to contain a water sample from which the organic compounds are purged; and

a sparger extending from the housing and disposed in the sample vessel with the sample vessel being attached to the housing.

2. A system according to claim 1, wherein the sample vessel is configured to contain a water sample of about 40 mL.

3. A system according to claim 1, wherein a level of the water sample in the sample vessel ranges from about 2.5 inches to about 4 inches, and the distance between a fill line of the water sample and the top end of the sample vessel ranges from about 3.5 inches to about 5 inches.

4. A system according to claim 1, wherein the sample vessel includes a retaining member.

5. A system according to claim 4, wherein the retaining member includes threads.

6. A system according to claim 4, wherein the housing includes a complimentary retaining member.

7. A system according to claim 6, wherein the complimentary retaining member is a retaining tube nut.

8. A system according to claim 1, wherein the sample vessel is configured as a hollow body surrounding an internal volume and defining a longitudinal axis, the sample vessel having an open top end and a closed bottom end.

9. A system according to 8, wherein the top end of the sample vessel is in fluid communication with a manifold with the sample vessel being attached to the housing.

10. A system according to claim 1, wherein the sparger includes:

a tubular member comprising a top end attached to the housing and a bottom end distal the housing; and

a gas dispersal member attached to the bottom end of the tubular member, the gas dispersal member having a diameter that is smaller than an inside diameter of the sample vessel and is larger than an outer diameter of the tubular member, the gas dispersal member having a porous top surface for distributing gas.

11. A system according to claim 10, wherein the outer diameter of the tubular member ranges from about 0.063 inches to about 0.125 inches.

12. A system according to claim 10, wherein the gas dispersal member includes:

a porous member mounted to the bottom end, the porous member including a top major surface and a bottom major surface respectively facing in opposite longitudinal directions along longitudinal axis of the tubular member; and

a cap mounted to the porous member and forming with the porous member a volume extending over a major extent of the bottom major surface and communicating with the internal volume of the tubular member.

13. A system according to claim 12, wherein the porous member includes a porous metal frit.

14. A system according to claim 1, wherein the preconcentrator includes:

a tubular member;

a sorbent bed disposed in the tubular member; and

first and second porous retaining members disposed in the tubular member at opposite ends of the sorbent bed for retaining the sorbent bed,

wherein the first and second porous retaining members are constrained against movement by respective inwardly crimped portions of the tubular member.

15. A system according to claim 14, wherein the tubular member has an outer diameter of about 0.125 inches.

16. A system according to claim 14, further including a spacer member disposed in the tubular member between the sorbent bed and the second porous retaining member.

17. A system according to claim 14, further including at least one of ceramic wool or glass wool disposed in the tubular member between the sorbent bed and the second porous retaining member.

18. A system according to any one of claims 14, wherein the sorbent bed includes a hydrophobic adsorbent material.

19. A system according to claim 14, wherein at least one of the porous retaining members includes a porous metal frit.

20. A system according to claim 1, wherein the sparger includes:

a tubular member comprising a top end attached to the housing and a bottom end distal the housing; and

a gas dispersal member attached to the bottom end of the tubular member, the gas dispersal member having a diameter that closely corresponds to an inside diameter of the sample vessel and having a porous top surface for distributing gas across substantially the entire interior diameter of the sample vessel at the bottom end.