Overall, it was generally found that the worker flames provided better signal characteristics in each mode. For example, S2* emission produced S/N values that were as much as 10 times greater in the worker flames than in the analytical flame. Interestingly,however, S2* emission in the worker flames was also found to be consistently quadratic, as opposed to the shifting response slope observed for the analytical flame in Fig 4. As a result, this S/N enhancement reduced to a factor near 2 at lower concentrations and the MDL was little changed.