Particle or cell analyzer and method

1. A particle analyzing apparatus comprising:

a capillary tube having an internal cross-sectional area, a first end and a second end opposite to the first end, said first end being adapted to be suspended for direct immersion into a sample fluid containing particles to be analyzed, said capillary tube including an analyzing region;

a source of light;

an optical system configured to receive and focus the light from said source to form and direct a rectangular beam through said capillary to define the analyzing region in said capillary tube;

a pump connected to the second end of the capillary tube, said pump being adapted to be capable of drawing a known volume of the sample fluid through the first end into the capillary tube and passing through said analyzing region;

at least one first detector for detecting fluorescent light emitted by particles excited by said beam; and

a tee structure having a first, second, and third connections;

a first conduit extending from the first connection and connected to the second end of the capillary tube;

a second conduit and a valve connected to the second connection and a waste dump; and

said pump is connected to the third connection;

whereby when the valve is closed, the pump draws the sample fluid from the first end of the capillary tube through said capillary tube, and wherein the second conduit has an internal cross-sectional area that is larger than the cross-sectional area of the capillary tube such that when the valve is opened the pump discharges substantially all the fluid sample previously drawn through the capillary tube to the waste dump.

2. The particle analyzing apparatus of claim 1 further comprising a second detector for detecting light scattered by particles which pass through said analyzing region.

3. The particle analyzing apparatus of claim 1 comprising a plurality of first detectors for detecting light from particles which fluoresce at different wavelengths.

4. The particle analyzing apparatus of claim 1 in which said second detector detects the electrical impedance of particles which pass through said analyzing region.

5. The particle analyzer apparatus of claim 1 in which said capillary tube is provided with a microchannel.

6. The particle analyzing apparatus of claim 1 in which said capillary tube has a rectangular internal cross-section.

7. The particle analyzing apparatus of claim 1 in which said capillary tube has a circular internal cross-section.

8. The particle analyzing apparatus of claim 2 further comprising a beam blocker for blocking direct transmission of illumination from said beam to the second detector.

9. The particle analyzing apparatus of claim 1 in which said pump is configured to draw the sample fluid at a constant rate.

10. The particle analyzing apparatus of claim 1 in which said pump is an electrically operated pump.

11. The particle analyzing apparatus of claim 1 in which said pump is a syringe pump.

12. The particle analyzing apparatus of claim 11 in which said syringe pump comprises a plunger moveable in a predetermined manner.

13. The particle analyzing apparatus of claim 1 in which said at least one first detector includes:

means for gathering fluorescent light emitted by particles in said analyzing region;

a beam splitter for receiving said gathered light and reflecting light above a predetermined wavelength and passing light below said predetermined wavelength,

a first detecting means for receiving the transmitted light and providing a first output signal for particles tagged to emit light below said predetermined wavelength,

a second detecting means for receiving the reflected light and providing a second output signal for particles tagged to emit light above said predetermined wavelength.

14. The particle analyzing apparatus of claim 13 in which said predetermined wavelength is 620 nm, said light below said predetermined wavelength is 580 nm, and above said predetermined wavelength is 675 nm.

15. The particle analyzing apparatus of claim 14 further comprising a filter interposed between the beam splitter and each detecting means for passing light at 580 nm and 675 nm, respectively.

16. The particle analyzing apparatus as in claim 13 in which said means for gathering the fluorescent light emitted by particles comprises:

a lens for collecting the light, and

a slit positioned in front of said at least one first detector to define the analyzing region observed by said detector.

17. The particle analyzing apparatus of claim 1 in which said optical system comprises a cylindrical lens.

18. The particle analyzing apparatus of claim 1 in which said capillary tube is selected to have internal cross-section dimensions which causes substantially all particles to be singulated as they pass through said volume.

19. The particle analyzing apparatus of claim 1 further comprising a movable member configured to support a plurality of vials containing sample fluids.