The Series 100 Flame Photometric Detector GC from AGC Instruments is
designed to give a response to sulphur and phosphorous compounds, has a
selectivity achieved by the inclusion of filters which will only allow
wavelengths characteristic of these elements to pass (380nm for sulphur
and 526 nm for phosphorus).
If only one reducing flame is used phosphorus emission is a linear
function of the quantity, while the emission from sulphur is a
logarithmic function of the quantity, this latter depending also on the
hydrocarbon part of the molecule so that an accurate response
calibration for each component injected is required.
Furthermore, with the simultaneous combustion of sulphur and
hydrocarbon compounds in the reducing flame an undesirable “quenching”
effect occurs, bringing about the reduction, or even the total
extinction of sulphur emission. In order to overcome these problems, the
AGC Instruments FPD uses an oxidising flame where the components
eluting from the column are first burnt.