Localized Surface Plasmon Resonance Mercury Detection System and Methods

• US 20140333933A1
• Filed: 01/10/2013
• Published: 11/13/2014
• Est. Priority Date: 01/11/2012
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: James, Jay, Lucas, Donald, Crosby, Jeffrey Scott, Koshland, Catherine P.
• Granted Patent: US 9,291,557 B2
• Time in Patent Office: Days
• US Class Current: 356/432
• CPC Class Codes: G01J 2003/425 Reflectance
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01N 21/554 detecting the surface plasmon resonance of nanostructured metals, e.g. localised surface plasmon resonance
• CPC Class Codes: G01N 2201/088 Using a sensor fibre
• CPC Class Codes: G01N 33/0045 for Hg

Abstract

A mercury detection system that includes a flow cell having a mercury sensor, a light source and a light detector is provided. The mercury sensor includes a transparent substrate and a submonolayer of mercury absorbing nanoparticles, e.g., gold nanoparticles, on a surface of the substrate. Methods of determining whether mercury is present in a sample using the mercury sensors are also provided. The subject mercury detection systems and methods find use in a variety of different applications, including mercury detecting applications.

Claims

1. A mercury detection system comprising:

a flow cell comprising a mercury sensor, wherein the mercury sensor comprises;

a transparent substrate; and

a submonolayer of gold nanoparticles on a surface of the substrate;

a light source; and

a light detector.

2. The mercury detection system of claim 1, wherein the submonolayer has a density of 5×

10¹² gold nanoparticles/cm² or less.

3. The mercury detection system of claim 1, wherein the gold nanoparticles are spherical.

4. The mercury detection system of claim 1, wherein the gold nanoparticles have an elongated shape.

5. The mercury detection system of claim 4, wherein the gold nanoparticles have an aspect ratio of 2 or more.

6. The mercury detection system of claim 4, wherein the gold nanoparticles have a surface area to volume ratio of 0.2 or more.

7. The mercury detection system of claim 1, wherein the nanoparticles are substantially free of a surface coating.

8. The mercury detection system of claim 1, further comprising a gas source in communication with the flow cell and configured to provide a flow of a gas through the flow cell.

9. The mercury detection system of claim 1, wherein the light source comprises a visible light source.

10. The mercury detection system of claim 1, wherein the light detector comprises a UV-Vis photodetector.

11. The mercury detection system of claim 1, wherein the system is configured to detect mercury vapor at a concentration of 100 μ

g/m³ or less.

12. A method for determining whether mercury is present in a sample, the method comprising:

contacting a sample to a mercury sensor comprising;

a transparent substrate; and

a submonolayer of gold nanoparticles on a surface of the substrate;

directing light from a light source to the sample-contacted mercury sensor; and

detecting a change in visible light absorbance of the gold nanoparticles to determine whether mercury is present in the sample.

13. The method of claim 12, wherein the contacting comprises flowing a gaseous sample through a flow cell comprising the mercury sensor.

14. The method of claim 12, further comprising quantifying the amount of mercury in the sample.

15. The method of claim 14, wherein the quantifying comprises determining the amount of mercury in the sample based on the rate of change in the localized surface plasmon resonance wavelength of the gold nanoparticles.

16. The method of claim 14, wherein the quantifying comprises determining the amount of mercury in the sample based on the rate of change of the absorbance (A) at wavelength (λ

) bands of greatest slope (dA/dλ

) near the localized surface plasmon resonant peak.

17. The method of claim 12, wherein the contacting comprises flowing a gaseous sample through a nozzle perpendicular to the mercury sensor.

18. The method of claim 12, further comprising contacting the sensor with water vapor before contacting the sample to the sensor.

19. The method of claim 12, further comprising regenerating the mercury sensor.

20. The method of claim 19, wherein the regenerating comprises heating the mercury sensor.