Capillary stop-flow junction having improved stability against accidental fluid flow

A vent-assisted capillary stop-flow junction comprising a housing surrounded by a gaseous atmosphere and an electronic instrument into which said housing removably fits, wherein (1) said housing comprising:

• a. an internal chamber;
• b. liquid receiving means for accepting a liquid;
• c. a capillary channel connecting said liquid receiving means to said chamber;
• and
• d. a channel leading out of said chamber and connecting said chamber to the atmosphere and surrounding said housing;
• (2) said electronic instrument comprises means for selectively closing said channel and sealing said chamber from the atmosphere;
• wherein when (1) said means for selectively closing is activated and gas is trapped in said capillary passageway and said chamber and (2) said liquid is concurrently applied to said means for accepting a liquid, said liquid flows through said capillary channel, compresses air trapped in said housing by said means for trapping, and stops flowing at said stop-flow junction.

A method for increasing stability of a capillary stop-flow junction in a housing surrounded by a gaseous atmosphere, which comprises the steps of:

• (1) providing a housing having:
• i. an internal chamber of non-capillary dimensions;
• ii. liquid receiving means for accepting a liquid;
• iii. a capillary channel connecting said sample receiving means to said chamber;
• iv. said stop-flow junction at the intersection of said capillary channel and said chamber;
• and
• v. a venting channel leading out of said chamber and connecting said chamber to the atmosphere surrounding said housing;
• (2) inserting said housing into a device having means for selectively closing said venting channel and sealing said chamber from the atmosphere;
• and
• (3) closing said venting channel prior to applying said liquid to said means for accepting a liquid, whereby said liquid flows through said capillary channel and stops flowing at said stop-flow junction.