Method and apparatus for detecting low concentrations of (bio) chemical components present in a test medium using surface plasmon resonance
First Claim
1. In a method for detecting low concentrations of at least one chemical component present in a test medium in a test cell, the test cell having a metal layer as sub wall with an external glass prism, using the surface plasmon resonance effect in which a light ray polarized in the plane of incidence is coupled in via the prism and, after attenuated total reflection, is coupled out and the intensity thereof is measured, the incidence angle position of the resonance curve being determined under the influence of change caused in the dielectric constant of the test medium near the metal layer by the chemical component, the improvement comprising providing the metal layer as an array of metal layer strips, each strip being provided with a different selector from a selector array of one type, and simultaneously determining concentrations or concentration changes of one or more components in the test medium through one or more differential measurements caused by a preferential association between each component and such a selector.
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Abstract
A method and an apparatus for detecting low concentrations of at least one (bio-) chemical component present in a test medium in a test cell, having a metal layer as sub wall with an external glass prism, using the surface plasmon resonance effect. A light ray is coupled in and, after attenuated total reflection, is coupled out and the intensity thereof is measured. The incidence angle position of the resonance curve is determined under the influence of the change, caused by the component, in the dielectric constant of the test medium near the metal layer. An adjustable selector is applied to the metal layer, in order to influence the incidence angle position of the resonance curve, through which the concentrations or concentration changes of one or more components in the test medium can be simultaneously determined through one or more differential measurements. A preferential association and therefor a higher concentration at the metal layer of one component above another is brought about.
86 Citations
12 Claims
- 1. In a method for detecting low concentrations of at least one chemical component present in a test medium in a test cell, the test cell having a metal layer as sub wall with an external glass prism, using the surface plasmon resonance effect in which a light ray polarized in the plane of incidence is coupled in via the prism and, after attenuated total reflection, is coupled out and the intensity thereof is measured, the incidence angle position of the resonance curve being determined under the influence of change caused in the dielectric constant of the test medium near the metal layer by the chemical component, the improvement comprising providing the metal layer as an array of metal layer strips, each strip being provided with a different selector from a selector array of one type, and simultaneously determining concentrations or concentration changes of one or more components in the test medium through one or more differential measurements caused by a preferential association between each component and such a selector.
- 2. The method according toclaim 1, wherein the selector is a variable potential thorugh which, in the differential measurement, a potential-dependent preferential adsorption of the one component above the other is achieved.
- 6. In an apparatus for detecting low concentrations of a least one chemical component present in a test medium using the surface plasmon rresonance effect, which apparatus is provided with a test cell for the test medium having a metal layer as sub wall with an external prism, a monochromatic light source for coupling in via the prism a light ray polarized in the plane of incidence in order to excite a surface plasmon wave in th metal layer, and at least one detector for measuring the intensity occurring with attenuated total reflection in the light ray coupled out, the incidence angle position of the reference curve changing due to the change in the dielectric constant of the test medium near the metal layer caused by the chemical component, the improvement comprising providing the metal layer as an array of metal layer strips, that each strip is provided with a different selector from a selector array of one type, and including means for simultaneously determining through one or more differential measurements due to a preferential association between one component and such a selector concentrations or concentration changes of one or more components in the test medium.
Specification