Nonaqueous Backscattering Interferometric Methods

• US 20130021608A1
• Filed: 02/22/2012
• Published: 01/24/2013
• Est. Priority Date: 02/22/2011
• Status: Active Grant

• Current Assignee: Lehigh University, Vanderbilt University
• Original Assignee: Vanderbilt University
• Inventors: Bornhop, Darryl J., Flowers, Robert A., Miller, Esther Pesciotta
• Granted Patent: US 9,562,853 B2
• Time in Patent Office: Days
• US Class Current: 356/342
• CPC Class Codes: G01N 2021/4709 Backscatter
• CPC Class Codes: G01N 21/45 using interferometric methods; using Schlieren methods

Abstract

Disclosed are improved optical detection methods comprising multiplexed interferometric detection systems and methods for determining a characteristic property of a non-aqueous sample, together with various applications of the disclosed techniques.

Claims

1. A method for determining a characteristic property of a non-aqueous sample comprising the steps of:

a. providing an apparatus adapted for performing light scattering interferometry, the apparatus comprising

i. a substrate;

ii. a channel formed in the substrate capable of receiving a non-aqueous sample to be analyzed;

iii. a light source for generating a light beam;

iv. a photodetector for receiving scattered light and generating intensity signals; and

v. at least one signal analyzer capable of receiving the intensity signals and determining therefrom one or more characteristic properties of the non-aqueous sample; and

b. interrogating the non-aqueous sample using light scattering interferometry.

2. The method of claim 1, wherein interrogating comprises detecting scattered light on the photodetector, and wherein the scattered light comprises a plurality of interference fringe patterns.

3. The method of claim 1, wherein interrogating comprises detecting backscattered light on the photodetector, and wherein the scattered light comprises a plurality of interference fringe patterns.

4. The method of claim 1, wherein the light source comprises a HeNe laser.

5. The method of claim 1, wherein the light source comprises a diode laser.

6. The method of claim 1, wherein the non-aqueous sample is interrogated in at least two discrete locations along a length of the channel substantially simultaneously.

7. The method of claim 1, further comprising determining one or more characteristic properties of the non-aqueous sample from the intensity signals.

8. The method of claim 7, wherein at least one of the one or more characteristic properties comprises a change in conformation, structure, charge, level of hydration, or a combination thereof.

9. The method of claim 1, wherein the non-aqueous sample comprises a plurality of individual sample and/or reference compounds, each separated by a volume of air in the channel.

10. A method for determining a characteristic property of a non-aqueous sample comprising the steps of:

a. providing a substrate having a channel formed therein for reception of a non-aqueous sample to be analyzed;

b. introducing a non-aqueous sample to be analyzed into the channel;

c. directing a light beam from a light source onto the substrate such that the light beam is incident on at least a portion of the non-aqueous sample to generate scattered light through reflective and refractive interaction of the light beam with a substrate/channel interface, and the non-aqueous sample, wherein the scattered light comprising interference fringe patterns including a plurality of spaced light bands whose positions shift in response to changes in the refractive index of the sample;

d. detecting positional shifts in the light bands; and

e. determining the characteristic property of the sample from the positional shifts of the light bands in the interference fringe patterns.

11. The method of claim 10, wherein the scattered light is incident on a photodetector array.

12. The method of claim 10, wherein e) comprises determining a plurality of characteristic properties of the non-aqueous sample from the interference fringe patterns generated in the channel.

13. The method of claim 10, wherein the positional shifts in the light bands correspond to a chemical event occurring in the non-aqueous sample.

14. The method of claim 10, wherein the substrate and channel together comprise a capillary tube.

15. The method of claim 10, wherein the substrate and channel together comprise a microfluidic device.

16. The method of claim 15, wherein the microfluidic device comprises a silica substrate and an etched channel formed in the substrate for reception of a sample, the channel having a cross sectional shape.

17. The method of claim 16, wherein the cross sectional shape is substantially circular.

18. The method of claim 16, wherein the cross sectional shape is generally semi-circular.

19. The method of claim 10, wherein the light beam is produced by a laser.

20. The method of claim 10, further comprising the step of performing a separation on the sample prior to the determining the characteristic property step.