Measurementof Plasma Phenytoinby EMIT Ifl the Monarch CentrifugalAnalyzer : Studies on the Eliminationof Within

We investigated the measurement of phenytoin in plasma by the EMIT#{174} method, in the Monarch centrifugal analyzer. When we used the standard protocol supplied by Instrumentation Laboratory, significant drift was observed across a full rotor loaded with 31 replicates of a single specimen. Although the cause remains obscure, the drift was eliminated by using a load-spin-reload-spin procedure. This makes it possible to analyze large batches of samples without excessive use of standards and reagents.