In order to best investigate this, analyte emission in three different modes (S2*, HSO*, and HPO*) was monitored through the worker flame view port using a large quartz light guide(150 mm × 18 mm o.d.) leading to the PMT. As well, the central channel of the SS mFPD was entirely extended to 2 mm wide to further facilitate analyte chemiluminescence, as mentioned earlier. Optimized worker flame gas flows for sulfur emission (S2* and HSO*) used 20 mL/min oxygen and 100 mL/min hydrogen, while phosphorus emission used 20 mL/min oxygen and 120 mL/min hydrogen. Under their respective optimum conditions, analytes were then measured in the analytical flame and worker flame monitoring modes and the results were directly compared