Simultaneous high-performance liquid chromatographic determination of salicylates in whole blood, plasma and isolated erythrocytes.

A method using liquid-liquid extraction has been developed for the isolation of acetylsalicylic acid and its metabolites, salicylic, gentisic or possibly salicyluric acids, from whole blood, isolated erythrocytes and plasma. Methylene chloride proved to be the best of the organic solvents tested. For whole blood and isolated erythrocytes it was necessary to carry out haemolysis prior to their extraction. The high-performance liquid chromatographic conditions for the quantitation of acetylsalicylic acid and its metabolites from samples of whole blood, erythrocytes and whole plasma were optimized. Separation was performed using reversed-phase chromatography on Separon SGX C18 and ultraviolet detection at 236 nm. A mixture of methanol-water (80:100, v/v) was the mobile phase, acidified with perchloric acid to pH 2.5.