A flame photometric detector for a process gas chromatograph is provided. The flame photometric detector includes a combustion chamber body defining a combustion chamber therein. A sample inlet tube is configured to introduce a process gas sample into the combustion chamber. An ignitor is configured to initiate combustion within the combustion chamber. A thermocouple assembly is configured to provide an indication of temperature within the combustion chamber. The sample tube has an end that is adjustable relative to the combustion chamber.