Author (Your Name)

Sara Beth Lovitz, Colby College

Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Chemistry Dept.


D. Whitney King

Second Advisor

Rebecca Conry


The Fe(II)-catalyzed oxidation of luminol has been a well-accepted chemiluminescence method for the trace and ultra-trace analysis of Fe(II) and Fe(III) in natural waters. Investigation into this chemiluminescence system has shown that COlg) is essential to Fe-catalyzed luminol chemiluminescence. In absence of CO2(g) there is no chemiluminescent signal. These reactions worked well in the past because CO2 is present in most laboratory H20 supplies. Intentional saturation of CO2 results in a 5-fold increase for this conventional system. We propose a mechanism for CO 2(g) enhancement that includes formation of a CO2-superoxide intermediate, which serves as the oxidant of luminol to initiate formation of the luminol radical and subsequent chemiluminescent reactions. Given the new mechanistic understanding of the Fe-luminol system we have optimized a FIA technique in terms of pH and reagent flow rates. The pH dependence of the system was modeled in terms of, and is in good agreement with, observed experimental results. With the incorporation of CO2(g), detection limits can be improved to below 100 picomolar.


Chemiluminescence, Carbon dioxide, Iron, Water chemistry

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