Enzymatic method for the determination of tellurite ions

A simple method for the quantitative determination of tellurite ions in aqueous media including blood plasma or serum is described. This assay is based on the selective and potent inhibition of a Zn2+-glycerophosphocholine phosphocholine phosphodiesterase by tellurite ions in the presence of tetramethylammonium ions. The assay method, which showed a good relationship between the enzyme inhibition and the amount of tellurite ions (50 nM-5 μM), was found to be rapid (< 5 min), reproducible (mean C.V., 6.5%), and at the same time, sensitive, showing a low limit of detection (50 nmol). Based on this technique, the removal of tellurites by thiols, and the kinetics for the uptake of tellurite ions in blood were investigated.