Nickel Colorimetric Assay Kit

Nickel is one of four ferromagnetic elements (symbol Ni, at. Num. 28). Several enzymes depend on nickel for activity, including some ureases, carbon monoxide dehydrogenases (methane forming enzymes which reduce CO₂ to CH₄) and some hydrogenases which allow the production or removal of H2. Most of these activities are found in the archaebacteria. Nickel forms complexes with sulfhydryl compounds with significant absorbance in the UV/visible region in the presence of other ions. BioVision’s Nickel Assay kit provides a simple method of quantifying Ni²ᶧ in a variety of samples. The assay takes advantage of reaction of Ni²ᶧ with mercaptoethanol in borate buffer to form a complex with strong absorbance bands from ~300 to 600 nm. Fe²ᶧ and Co²ᶧ interfere with the assay, therefore extra steps (as described below) must be taken to subtract the interference in order to determine the correct Nickel concentration in mixed samples. Other ions tested (Mn²ᶧ, Cu²ᶧ, Zn²ᶧ) do not interfere with the assay, presumably no other ionic species are present in high enough concentration to interfere with the reaction. The assay is a simple method of quantifying Ni²ᶧ in a variety of samples, which gives a linear range of 2 to 50 nmol Nickel containing less than 25 nmol Cobalt.