EFFECT OF TEMPERATURE AND SOME COMMON METALS ON THE STABILITY OF VOLATILE ANESTHETIC ENTONOX MIXTURES

Thermal stability of pressurised ready-to-use volatile liquid anaesthe tic mixtures (halothane, isoflurane and enflurane) in Entonox (commerc ially available premixed 50% N2O, 50% O-2 mixture) were investigated a t temperatures of 20, 258, 400, 503 and 602 degrees C on glass, stainl ess steel, copper and aluminium by gas chromatography and GC-MS. It wa s found that most of the decomposition products formed were halogenate d compounds and the observed thermal stabilities in glass, stainless s teel and copper allowed a thermal treatment up to 250 degrees C withou t any decomposition problem. Aluminium was found to be the most effect ive metal at causing decomposition of the anaesthetic mixtures even at lower temperatures. (C) 1998 Elsevier Science B.V. All rights reserve d.