Determination of metallothionein at the femtomole level by constant current stripping chronopotentiometry

Metallothionein (MT) from rabbit liver was analyzed by differential pulse p olarography, cyclic voltammetry, square wave voltammetry, and chronopotenti ometric stripping analysis (CPSA) with a hanging mercury drop electrode und er various conditions. The highest sensitivity of the AIT determination was obtained with CPSA which produced a well-developed peak H due to catalytic hydrogen evolution at highly negative potentials. The highest peak H was o btained in borate buffer close to pH 8.0. In this medium, subnanomolar conc entrations of NIT were detectable. In the adsorptive transfer stripping (me dium exchange) experiments, determination of few femtomoles of MT in 5-muL aliquots of the analyte was possible. CPSA determination of AIT in various tissues of carp (Cyprinus carpio) yielded values in agreement with the publ ished data.