Pregledni rad
Preparation of calibration mixtures of gases and vapours with air
Mirka Fugaš
; Institut za medicinska istraživanja i medicinu rada u Zagrebu
Ranka Pauković
; Institut za medicinska istraživanja i medicinu rada u Zagrebu
Z. Topolnik
; Institut za medicinska istraživanja i medicinu rada u Zagrebu
Sažetak
In the course of our work we tried out a few static and a few dynamic systems for the preparation of known mixtures of gases and vapours with air. We had satisfactory experience with both systems. Dynamic systems were used for long-term investigation as e. g. testing of filters of respirators and masks, as well as the exposure of experimental animals to contaminated atmosphere. The static systems were used to calibrate indicating instruments, determine absorption efficiency of collection devices and for the evaluation of new analytical methods. The known mixture was prepared in one bottle for small samples and in a system of 5 bottles for large ones. Both methods have been described in literature. However, the following modifications were introduced by us: (1) a different system of ampoule crushing, (2) the use of an electromagnetic stirrer when a homogeneous composition of the mixture cannot be achieved by simple mixing, and (3) an easier method of preparing five bottles with equal initial concentrations. It consisted in weighing one ampoule with a tenfold amount of substance whose mixture with air is to be prepared, instead of five ampoules with exactly the same quantities. This one ampoule serves for preparing the concentration in one bottle from which one tenth of barometric pressure is transferred into each of five evacuated bottles. This method has been checked and has given satisfactory results. ln addition of being quicker and simpler, it has the advantage of facilitating the preparation of very large dilutions.
Ključne riječi
Hrčak ID:
183079
URI
Datum izdavanja:
23.6.1959.
Posjeta: 692 *