Morphine: its quantitative determination in nanogram amounts in small samples of whole blood by electron-capture gas chromatography.

A method for the determination of nanogram quantities of morphine in hemolyzed whole blood taken post mortem, or other blood samples of poor quality, has been developed. Morphine was extracted into ethyl acetate from blood at pH 8.7-9.0, and purified by absorption onto a column of acid aluminium oxide and elution with methanol. Nalorphine was added as an internal standard, the compounds derivatized with pentafluoropropionic acid anhydride, and the derivatives formed quantified by electron-capture gas chromatography. The recovery of morphine added to whole blood was 83%, the coefficient of variation 6.7%. The method is capable of measuring morphine concentrations of 1 ng/g in 0.1-0.2 g of post-mortem blood.