Molecular sieve sensors for selective detection at the nanogram level

• US 5,151,110 A
• Filed: 09/11/1990
• Issued: 09/29/1992
• Est. Priority Date: 09/11/1990
• Status: Expired due to Term

• Current Assignee: The University of New Mexico
• Original Assignee: The University of New Mexico
• Inventors: Frye, Gregory C., Brown, Kelly D., Brinker, Charles J., Bein, Thomas
• Primary Examiner(s): SPITZER, ROBERT H
• Application Number:
  US07/580,373
• Time in Patent Office: 749 Days
• Field of Search: 55/208, 55/270, 55/274, 55/389, 55/197, 55/386, 55/18-21, 55/74, 55/75
• US Class Current: 95/140
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/11 Clays
• CPC Class Codes: B01D 2253/202 Polymeric adsorbents
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2257/502 Carbon monoxide
• CPC Class Codes: B01D 2257/702 Hydrocarbons
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0426 Bulk waves, e.g. quartz crystal microbalance, torsional waves
• 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 30/00 Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation G01N3/00, G01N5/00, G01N7/00, G01N9/00, G01N11/00, G01N13/00, G01N15/00, G01N17/00, G01N19/00, G01N21/00, G01N22/00, G01N23/00, G01N24/00, G01N25/00, G01N27/00, G01N29/00 take precedence

Abstract

The invention relates to a selective chemical sensor for selective detection of chemical entities even at the nanogram level. The invention further relates to methods of using the sensor. The sensor comprises:

(a) a piezoelectric substrate capable of detecting mass changes resulting from adsorption of material thereon; and

(b) a coating applied to the substrate, which selectively sorbs chemical entities of a size smaller than a preselected magnitude.

Claims

1. A method of selectively detecting the presence of a chemical entity within an environment comprising placing a selective chemical sensor in said environment and detecting mass changes of the piezoelectric surface resulting from sorption of material thereon, said chemical sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a preselected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (a) is a surface acoustic wave (SAW) device or a quartz crystal microbalance (QCM) device,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability, and

wherein said film is an inorganic silica matrix having zeolite crystals embedded therein.

2. A method of selectively detecting the presence of a chemical entity within an environment comprising placing a selective chemical sensor in said environment and detecting mass changes of the piezoelectric surface resulting from sorption of material thereon, said chemical sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a preselected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (a) is a surface acoustic wave (SAW) device or a quartz crystal microbalance (QCM) device,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability,

wherein said film is an inorganic matrix having zeolite crystals embedded therein, and

wherein said matrix is selected from the group comprising sol-gel derived glasses, polymers and clay.

3. A chemical sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a pre-selected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability, and

wherein said film is an inorganic silica matrix having zeolite crystals embedded therein.

4. A sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a pre-selected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability,

wherein said film is selected from the group comprising sol-gel derived glasses, polymers and clays.

5. A sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a pre-selected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability, and

wherein the pores of said zeolite crystals are modified so as to be Lewis or Bronsted acidic or basic.

6. A sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a pre-selected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability, and

wherein the pores of said zeolite crystals are modified so as to provide intrazeolite ligation by the presence of metal ions.

7. A sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a pre-selected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (b) is a film containing zeolite crystals, wherein the pores within said zeolite crystals provide molecule sieving capability, and

wherein said film is an alumina, boro-aluminosilicate, titania, hydrolyzed diethoxydiphenylsilane, or silane rubber matrix containing zeolite crystals.

8. A sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of material thereon; and

(b) a coating applied to said substrate, which selectively sorbs chemical entities of a size less than a pre-selected magnitude, wherein the chemical entity to be detected is CO or a hydrocarbon,

wherein element (b) is a solid, non-porous, inorganic matrix with porous zeolite crystals embedded therein.

9. A selective chemical sensor comprising:

(a) a piezoelectric substrate capable of detecting mass changes resulting from sorption of materials thereon;

(b) a coating applied to said substrate, wherein said coating comprises a solid, non-porous, inorganic matrix and porous zeolite crystals contained within said matrix, wherein the pores of said zeolite crystals selectively sorb chemical entities of a size less than a preselected magnitude.

10. A chemical sensor according to claim 9, wherein said inorganic matrix is a silicon matrix having a thickness of about 0.001-10 microns and said pores of said zeolite crystals have a diameter of about 0.25-1.2 nm.

11. A sensor according to claim 10, wherein said coating is a single layer of zeolite crystals protruding from an amorphous SiO₂ matrix.

12. A sensor according to claim 11 wherein element (a) is a surface acoustic wave (SAW) device.