Patent ID: 8486333

Claim:
A fluid analysis rotor comprising: a rotational axis; a reagent chamber in fluid contact with a mixing chamber through a reagent conduit; and, a sample chamber in fluid contact with the mixing chamber through a metering tube comprising a capillary port at the mixing chamber; wherein, the rotor is configured so that when the rotor is not rotating about the axis, a liquid reagent in the reagent chamber does not flow into the mixing chamber through the conduit, and liquid sample in the sample chamber does not flow into the mixing chamber through the capillary port; wherein at a first rotor rotation speed, the liquid sample fills the metering tube but is retained from flowing into the mixing chamber by a meniscus surface tension of the liquid sample at the capillary port; and, wherein the rotor structure is configured so that at a second rotor rotation speed faster than the first rotation speed, the liquid reagent flows to contact the sample meniscus at the capillary port in the mixing chamber, thus breaking the sample meniscus surface tension so that the sample flows from the metering tube into the mixing chamber.