Wet and dry chemistry kits for total creatine kinase activity using a microfabricated, planar, small-volume, amperometric cell Original Research Article

A novel microfabricated amperometric microcell is used for total creatine kinase (CK) activity determination. The microcell employs a photolithograpically prepared flat form electrode pair for detection. The enzyme-catalyzed reaction takes place in a thin liquid film, supported by a replaceable porous, hydrophillic membrane, resting on the working electrode surface. Simple, two electrode, amperometry was used, to avoid overvoltage shocks caused by “open” circuits. An electrochemically prepared size-exclusion membrane was utilized on the working electrode to provide selectivity for the amperometric detection of hydrogen peroxide. Two different analytical reaction sequences following the CK catalyzed creatine phosphate hydrolysis were investigated. Both result in hydrogen peroxide production. The rate of hydrogen peroxide production is proportional to the total CK activity, and it is followed after the dispensation of sample into the microcell. The slope of the amperometric current–time curve is evaluated as the analytical signal.