Direct spectrophotometric determination of thebaine in Arya II population capsules of Papaver bracteatum Lindl.

A simple spectrophotometric determination of thebaine based on the complexation reaction with bromcresol green was developed. The yellow complex was extracted with chloroform over the pH 1.5--4.5 range. The solution of the complex in chloroform showed the maximum absorption at 415 nm and obeyed Beer's law over the concentration range of 4.0--14.0 microgram/ml. The molar absorptivity of the complex was 1.9460 X 10(4). The ratio of thebaine to bromcresol green in the complex was 1:1. The method was applied successfully to the direct determination of thebaine in the Arya II population capsules of Papaver bracteatum Lindl. The thebaine content of the dried capsules was 3.14%.