Abstract: A probe for measuring the concentration of an alcohol, such as ethanol, in a liquid, such as water. The probe according to the invention has a membrane that is permeable for vapors of the alcohol but substantially impermeable for the liquid; a measuring chamber having an open end closed against the liquid by the membrane is provided and has an inlet and an outlet; a pump or other pressure means serves to feed a purge gas, such as air, via the inlet into and out of the measuring chamber; a valve is provided near the inlet for controlled passage of the purge gas through the chamber; a suitably dimensioned detector including a pellistor or a gas-sensitive resistor is arranged in the measuring chamber for quantitative detection of the alcohol and for generating an electrical signal in proportion with the detection.

Abstract: The gas detection apparatus comprises a holder for the temporary fixation of an associated package and which contains a contact surface. A hollow needle having a tip serves to penetrate a portion of the package which is freely exposed at the region of the contact surface. This hollow needle comprises at least two channels. An element serves for the essentially gas-tight connection of the hollow needle tip with the contact surface or the part of the package freely exposed therein. A component is connected by a connection line with one channel of the hollow needle. A suitable membrane-enclosed sensor, such as an amperometric sensor defining a sensor surface formed by a semi-permeable membrane, is preferably suspendingly arranged in the compartment. A preferably closable flushing or purging gas line communicates with the connection line and allows flushing the compartment, the connection line and the one channel.