Simultaneous determination of codeine and morphine in urine and blood by HPLC

A procedure is presented for the determination of nanogram quantities of codeine and morphine in biological specimens by HPLC. The quantitative method is based on hydrolysis of the urine samples followed by basic extraction of urine and blood with organic solvents. Separation by liquid chromatography is a reverse phase system on a Spherisorb-CN (5 micron) column with a mobile phase of 40% methanol and phosphate buffer, pH 6.8. The method separated the opiates for screening purposes and was used for confirmation of morphine detected by radioimmunoassay.