Effect of temperature and some common metals on the stability of volatile anaesthetic Entonox mixtures

Abstract

Thermal stability of pressurised ready-to-use volatile liquid anaesthetic mixtures (halothane, isoflurane and enflurane) in Entonox (commercially available premixed 50% N2O, 50% O-2 mixture) were investigated at temperatures of 20, 258, 400, 503 and 602 degrees C on glass, stainless steel, copper and aluminium by gas chromatography and GC-MS. It was found that most of the decomposition products formed were halogenated compounds and the observed thermal stabilities in glass, stainless steel and copper allowed a thermal treatment up to 250 degrees C without any decomposition problem. Aluminium was found to be the most effective metal at causing decomposition of the anaesthetic mixtures even at lower temperatures. (C) 1998 Elsevier Science B.V. All rights reserved.