DIRECT RESISTIVE HEATING AND TEMPERATURE MEASUREMENT OF METAL-CLAD CAPILLARY COLUMNS IN GAS CHROMATOGRAPHY AND RELATED SEPARATION TECHNIQUES

摘要

A system and method for high resolution gas chromatography involves the use of fused silica open tubular capillary columns (33) having a conductive exterior coating and an arrangement for electrically coupling a power source (21) to the coating to effect direct resistive heating of column (33) while controlling the temperature thereof. The control of temperature is achieved by measuring the resistance of the coating, correlating such resistance with the temperature of column (33), and increasing or decreasing the electrical power supplied to the coating to effect the adjustment in column (33) temperature. Because of the low thermal mass of column (33) and the conductive coating, temperature changes can be readily effected thereby improving the speed of separation and reducing the time interval between resolution of successive samples. The compact nature and low power demands of the system allow it to be operated as a portable unit.