The Determination of Blood Concentration of Melatonin by GC/MS-SIM

A method by GC/MS-quantitative technique with coffeine as ISTD which can determine Melatonin has been developed.The standard curve of Melatonin in blood is Y=0.0582+0.6067X(r=0.9994),the recoveries of five concentrations of 10,20,50,200,400 ng/mL are 74.34,90.39,94.39,81.98,86.10% respectively;and the precision within a day is 6.55%,the precision between days is 14.50%.We determined the blood concentration of Melatonin in rabbits after 30 mg/Kg Melatonin had been administered.The method is proved to be good enough to study pharmacokinetics of Melatonin.