Flow-injection spectrophotometric determination of adrenaline and dopamine with sodium hydroxide

A new, rapid and economical flow-injection method for determining adrenaline and dopamine is proposed on the basis of the hydrolysis of these compounds in alkaline medium. The method was optimized by using a spectrophotometer operating at lambda = 390 nm as detector. Calibration graphs were linear up to 2 x 10(-4) M with quantification limits of 2.5 x 10(-6) M and 3.3 x 10(-6) M for dopamine and adrenaline respectively. Flow-injection allows the measurement of 130 samples per hour. The method was successfully applied for the determination of catecholamines in pharmaceuticals.