The present invention provides a mobile power pack with fragrance feature is disclosed. The measuring cell comprises a fluid channel having an internal cross-section smaller than or equal to 1. The means for dispensing and restricting flow of a gas through the nozzle may be either a bypass piping having a flow control means or a stopper that operates to provide a constant but low volume flow of an inert gas such as nitrogen to the nozzle to prevent particle build up or crystallization from occurring.