Actinomycin D was weighed and dissolved in
methanol to produce a stock solution of 1 mg/ml.
This was diluted in blank plasma to obtain a 1g/ml
intermediate stock solution which was used to prepare
working standards of 100, 50, 20, 10, 5, 2
and 1 ng/ml in plasma. Fresh intermediate stock solutions and working standards were prepared at
monthly intervals.