Abstract: Estrogen has greater and greater influence on water environment.Even when the concentration of estrogen is as low as 0.1 ng/L,make fish will reverse sex.In order to find a highly sensitive and selective method to determine estrogen in complex samples,GS-Ms method,which does not need derivative reaction,is developed to determine ultratrace amounts of estrogen in water,including estrone,E1;17β-estradiol,E2;ethinyl estradiol,EE2.The results show that for estrogen,low-temperature injection port can effeciently improve sensitivity of that method.The optimized method has been validated with good linearity,precision and accuracy.Method detection limits (MDL) of each estrogen compounds are found to be 0.082 ng/L for E1,0.073 ng/L for  E2,and 0.065 ng/L for EE2,respectively.

Key words: estrogen;water, GC-MS;injection port;optimization