摘要 |
Sample analysis in a portable analytical instrument, preferably in the form of a gas chromatograph, benefits from temperature control of one or more zones in the instrument by way of thermal energy developed from an energy reservoir. In a preferred embodiment, analytical instrument performs chromatographic analysis and the selected zone comprises a temperature-controlled thermal chamber, or oven (124) which includes a heating unit (118), a temperature sensor (128), and a cooling unit (130). A separation column column (118) is positioned within the oven (124). The energy reservoir comprises a first reservoir (125) of heating fluid in the form of a compressed light hydrocarbon, a second reservoir (126) of a compressed inert gas, or a combination thereof. A controlled temperature in the oven (124) resulting from the operation of the heating unit (118) and/or cooling unit (130) may be effected in response to a control signal generated by a computer (122). A sample mixture passing through the column (118) is thereby exposed to a desired temperature profile according to a selected program so that the sample (111) will separate into its components for subsequent detection by a detector (124). <IMAGE> |