Vidicon spectrometer applied to simultaneous enzyme determinations.

Lactate dehydrogenase and alkaline phosphatase activities in the same medium can be determined simulataneously, at 350 and 550 nm, with a vidicon spectrometer. Substrate concentrations and ph have been made optimum for the combined analysis. These conditions result in activities for lactate dehydrogenase that are equivalent to those found by methods in common use, and activites for alkaline phosphatase that are about 31% below the maximum values that could be obtained with its substrate used at the same ph and temperature in the absence of NAD+ and lactate. However, activites measured by the simultaneous analysis were proportional to those obtained by other methods used in clinical laboratories, and the coefficients of variation were 2.3% for lactate dehydrogenase and 3% for alkaline phosphatase.