| 摘要 |
1,213,900. Etching. CESKOSLOVENSKA AKADEMIE VED. 31 Dec., 1968 [15 March; 1968], No. 61810/68. Heading B6J. [Also in Division C1] Glass capillaries for gas chromatography have their inner surfaces etched by gas or vapour, the gas a vapour, at a temperature at which it is unreactive, being introduced into the capillary and heated to a temperature and for a time sufficient to cause the etching. Preferably nitrogen, saturated with the gas, is introduced into the capillary, the capillary sealed at both ends and then heated to a temperature greater than 100‹ C., for example 450‹ C., for at least 30 minutes. After cooling, the capillary is flushed with an inert gas such as nitrogen while heated above 100‹ C. Etching gases suggested are gaseous hydrogen chloride, dichloromethane vapour, trifluoroethyl methyl ether vapour or an organic halogen derivative when on heating gives off gaseous hydrogen chloride or hydrogen fluoride. |
