摘要：A little modification of the methyl orange method for the estimation of morphine which was developed by Woods, et al., was investigated. p-Nitrobenzoyl morphine was used to make its methyl orange complex by Woods, et al. On the other hand, the present modification involves selective acetylation of morphine with acetic anhydride in the presence of sodium bicarbonate and the extraction of the product, 3-acetylmorphine with chloroform. The derivative was then estimated by complexing with methyl orange. This method could be applied to the estimation of morphine in biological fluid, urine or plasma. Estimation of morphine was not affected by normorphine which is one of the metabolites of morphine.
