Original Article Development of a High Performance Liquid Chromatography with Coulometric Electrochemical Detector Method for the Analysis of Morphine in Human Plasma

A HPLC method using reversed-phase chromatography coupled with a coulometric electrochemical detector (ECD) was developed for the determination of morphine in human plasma. Hydromorphone was selected as an internal standard. The compounds were extracted using solid-phase extraction with C18 cartridges and separated on a reversed-phase C18 column with the mobile phase consisting of 69 % v/v phosphate buffer pH 2.2 (5 mM sodium phosphate monobasic and 0.7 mM sodium dodecyl sulfate) and 31 % v/v acetonitrile. The working electrode of the ECD was set at +450 mV for analytical purposes. Under this condition, the limit of detection for morphine was 0.33 ng/mL, whereas the limit of quantitation was 1.88 ng/mL. The percen