Patent ID: 7497995

Claim:
A liquid transfer apparatus for transferring a sample liquid slug from a reservoir to a test site on a substrate surface comprising: an aspiration source; a dispensing source; a valve assembly movable between an aspiration condition and a dispensing condition; a manifold device providing a liquid aspiration conduit having a first aspiration port, in liquid communication with the aspiration source, and a second aspiration port, said manifold device further providing a liquid dispensing conduit having a first dispensing port, in liquid communication with the dispensing source, and a second dispensing port; and a liquid communication structure defining a dispensing orifice, said liquid communication structure and said manifold device cooperating to define a discrete sample path extending from the dispensing orifice and through at least a portion of said manifold device; said valve assembly and said manifold device being cooperatively associated such that: in said aspiration condition, the second aspiration port is fluidly coupled to said discrete sample path to enable selective aspiration of a liquid sample slug directly through said dispensing orifice, from the reservoir, and into at least a portion of the sample path, while the second dispensing port is fluidly decoupled from the sample path to prevent liquid communication with the dispensing source, and in said dispensing condition, the second dispensing port is fluidly coupled to the sample path to enable selective dispensing of at least one droplet of the liquid sample slug directly from said dispensing orifice to the test site, while the second aspiration port is fluidly decoupled from the sample path to prevent liquid communication with the aspiration source.