Rapid Colorimetric Method for the Quantitative Determination of Ethchlorvynol (Placidyl) in Serumand Urine

Abstract
A rapid, precise, colorimetric method for the determination of ethchlorvynol (Placidyl) in serum or urine is described. The method is based upon the formation of a chromogen when ethchlorvynol reacts with diphenylamine in a medium of sulfuric and acetic acids. The method uses 0.50 ml. of serum or urine and the chromogen follows Beer's law at 510 mμ with ethchlorvynol concentrations as high as 4 mg. per 100 ml. The coefficient of variation of the method is 3%. No interferences with the determination of ethchlorvynol in serum and urine by this method have been found.