Application of Alpha, Alpha-Dipyridyl Dye for Hydric Soil Identification.

Chemical dyes, including alpha, alpha-Dipyridyl, can be used to identify ferrous iron in hydric soil studies and aid in conducting wetland delineations. Indicator test strips containing alpha, alpha-Dipyridyl have been developed; however, limited data addresses the reliability of indicator test strips and questions remain regarding potential degradation of alpha, alpha-Dipyridyl in liquid and paper formulations. Laboratory studies found ferrous iron detection limits of 0.31 mg L^-1using both liquid and indicator test strips. The liquid dye and indicator test strips displayed similar reactivity in five soils under simulated field conditions. Results suggest that indicator test strips provide a useful tool for ferrous iron detection across a range of soil conditions. Degradation studies indicate that both liquid dye and indicator strips were impacted by light and heat exposure, with a loss of reactivity observed within as few as three days under extreme conditions. Maintaining both liquid dye and indicator strips in cool, dark conditions and testing reactivity with laboratory solutions will ensure the reliability of alpha, alpha-Dipyridyl results.