Background correction method for use in gas chromatography

A method of correcting for changes in background radiation in a plasma emission detector comprising a plurality of sensors associated with specific emission frequencies including a sensor associated with at least one principal carbon emission frequency and another sensor associated with a frequency of emission of another element,

• generating a calibration curve which correlates the response at the said other sensor in the absence of the other element of interest with the response at said carbon sensor by plotting the response at the sensor of interest in the absence of the element associated with that sensor against the response at the carbon sensor,
• storing said calibration curve in system memory,
• thereafter, measuring the signal response at said carbon sensor,
• simultaneously measuring the signal response at said other sensor,
• subtracting from the signal from said other sensor an amount determined from the calibration curve stored in said system memory.

A method of correcting for changes in background radiation in a plasma emission detector comprising a plurality of sensors associated with specific emission frequencies including a sensor associated with at least one principal carbon emission frequency and another sensor associated with a frequency of emission of another element,

• generating a calibration curve which correlates the response at the said other sensor in the absence of the other element of interest with the response at said carbon sensor,
• storing said calibration curve in system memory,
• thereafter, measuring the signal response at said carbon sensor,
• simultaneously measuring the signal response at said other sensor,
• subtracting from the signal from said other sensor an amount determined from the calibration curve stored in said system memory,
• wherein the generation of said calibration curve comprises the step of measuring the nitrogen content of the carrier gas used in the system.