Abstract: An analytical instrument and associated method for ascertaining gas transmission rates of a target-analyte through a capped mouth of a bottle. The instrument employs a unique fixture that includes (1) a selectively openable and closeable enclosure defining a chamber, and (2) a mounting post extending into the chamber. The post is configured and arranged to sealingly engage an inner surface of a capped bottle neck, wherein mounting of a capped bottle neck onto the post sealingly separates the chamber into a first compartment inside the mounted capped bottle neck and a second compartment outside the mounted capped bottle neck. The fixture is configured and arranged with passageways for introducing a pressurized target-analyte-containing fluid into the first compartment of the chamber and flushing the second compartment of the chamber with a target-analyte-free fluid.

Abstract: A needle valve with a hollow needle effective for permitting a portion of the fluid passing through the valve to flow throughout the valve and exit through any leaks in the valve, whereby any environmental fluid within the valve is displaced by the fluid passing through the valve.

Abstract: A sensor for detecting water vapor in a gaseous sample. The sensor comprises (a) an anode, (b) a cathode, (c) an electrolyte intermediate the anode and cathode, and (d) an inlet orifice through a central area of the anode or cathode through which the gaseous sample may be placed into contact with the electrolyte. The electrolyte can be retained on a porous electrical-insulating separator located between the interior-facing major surfaces of the anode and the cathode.