A new hypothesis of spectrochemical excitation is proposed to explain the region of uncertain detectability, whereby it is possible to formulate equations that will cover the two concentration ranges found in spectrographic analysis. The first concentration range occurs when in replicate analysis on the same material all results are detected, the second concentration range when some results in the replicates are not detected. An example is quoted where the over-all correlation for these two levels is 0.9972 and x2 for three degrees of freedom is found to be 0.12.
D. J. Hobbs and A. Iny, "The "Limit of Detection" in Spectrographic Analysis: Further Thoughts and Experiments," Appl. Spectrosc. 24, 522-526 (1970)