SPECTROPHOTOMETRIC DETERMINATION OF BARBITURIC-ACID

Barbituric acid reacts with chloral hydrate in alkaline media, after h eating for 1 min. at 100 degrees C to give an orangish yellow colour h aving maximum absorbance at 450 nm. The reaction is selective for barb ituric acid with 0.01 mg/ml as the visual limit of quantitation and pr ovides a basis for a new spectrophotometric determination. The colour reaction obeys Beer's Law from 0.001 to 0.6 mg/ml and the relative sta ndard deviation is 1.1%. The quantitative assessment of tolerable amou nts of other drugs is also studied.