Particle interaction characterization using overlapping scattering and concentration measurements

1. A particle interaction characterization instrument, comprising:

a flow cell for a liquid sample that includes suspended particles,

a light source positioned to illuminate the suspended particles in the liquid sample fluid in the sample vessel,

a first scattering detector positioned to receive light from the light source that has been scattered by the particles suspended in sample fluid in the sample vessel at at least one predetermined scattering angle,

an ultraviolet transmittance detector positioned to receive a portion of the light from the source that passes through the suspended particles without being absorbed or scattered, and

interaction analysis logic responsive to both the scattering detector and the ultraviolet detector, and being operative to derive at least one interaction property for the suspended particles.

2. The apparatus of claim 1 wherein the light source is an LED.

3. The apparatus of claim 1 wherein the light source is a 280 nm LED.

4. The apparatus of claim 1 wherein the flow cell has a cross section of 0.5 mm or less.

5. The apparatus of claim 1 wherein the light source is positioned to illuminate the flow cell independent of any optical fiber.

6. The apparatus of claim 1 wherein the interaction analysis logic includes dual-mode compensation logic that is operative to correct a scattering signal from the scattering detector based on an amount of light that reaches the ultraviolet detector.

7. The apparatus of claim 1 wherein the interaction analysis logic is operative to derive a B 22 value for the sample.

8. The apparatus of claim 1 wherein the instrument is operative to automatically perform a succession of simultaneous ultraviolet and scattering measurements.

9. A particle interaction characterization method, including the steps of:

illuminating particles suspended in a sample fluid with a light source,

detecting light from the step of illuminating that has been scattered by the particles,

detecting ultraviolet light from the step of illuminating that passes through the sample without being absorbed or scattered, and

deriving at least one interaction property for the suspended particles based on both results of the step of detecting scattered light and results of the step of detecting ultraviolet light.

10. The method of claim 9 wherein the step of detecting scattered light and the step of detecting ultraviolet light are performed simultaneously during the step of illuminating.

11. The method of claim 9 further including the step of correcting a scattering signal from the step of detecting scattered light based on an amount of light that reaches the ultraviolet detector.

12. A particle interaction characterization instrument, comprising:

means for illuminating particles suspended in a sample fluid,

means for detecting light from the means for illuminating that has been scattered by the particles,

means for detecting ultraviolet light from the means for illuminating that passes through the sample without being absorbed or scattered, and

means for deriving at least one interaction property for the sample based on both signals from the means for detecting scattered light and signals from the means for detecting ultraviolet light.

13. The method of claim 9 wherein the sample is a dilute protein sample.