The Narwhal determines Manganese concentration via a Formaldoxime colorimetric method. The Narwhal automatically samples the process stream and proceeds with chemistry addition: a buffer reagent is added, followed by the Formadoxime reagent, and finally a complexing reagent to promote color formation. The solution is mixed by exchanging the fluids between a syringe pump and measurement cell. Color formation (reddish-brown) becomes stronger with increasing concentrations of Manganese. Upon completion of the reaction an absorption measurement at 450nm is made that is proportional to Manganese concentration.