For instance, Fig. 3 illustrates this difference with typical images of both devices with and without sulfur emission present under normal operating conditions. As seen in Fig. 3A, the quartz tube mFPD exhibits a notable orange glow at the burner tips of the SS capillaries, while a dim background emission is also seen at the analytical flame. Fig 3B then demonstrates the same during sulfur analyte emission. Here again, even though blue S2* chemiluminescence can be clearly seen, the dominant orange background emission persists. As noted above, this results from in can descent glowing of the cement used to hold the flame burners in place . Spectral examination of this emission indicated that it produced an intense continuum spanning from 350 to 850 nm, and accordingly interfered with essentially all key analytical wavelengths for FPD measurement. As such, the resulting background emission and baseline noise observed in the quartz tube prototype can serve to inhibit the overall performance of the detector.