| CPC G01N 33/743 (2013.01) [G01N 30/724 (2013.01); G01N 33/6848 (2013.01); G01N 33/6851 (2013.01); H01J 49/0027 (2013.01); G01N 2458/15 (2013.01); H01J 49/00 (2013.01)] | 2 Claims |

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1. A method for determining the amount of 17β-estradiol and estrone in a human serum or plasma sample by mass spectrometry, the method comprising:
adding one or more deuterated internal standards of 17β-estradiol and/or estrone to a human serum or plasma sample containing 17β-estradiol and estrone to form a second sample;
subjecting the second sample to turbulent flow liquid chromatography to form a third sample;
purifying the third sample by high performance liquid chromatography to form a fourth sample;
ionizing the fourth sample with electrospray ionization to produce one or more ions of 17β-estradiol and estrone detectable by mass spectrometry;
determining the amounts of one or more ions of 17β-estradiol and estrone by tandem mass spectrometry, wherein the one or more ions of 17β-estradiol comprise an ion having a m/z ratio of 169.10±0.50; and
using the amounts of one or more ions and the amount of the ion having a m/z ratio of 169.10±0.50 from each of 17β-estradiol and estrone to determine the amounts of each of 17β-estradiol and estrone in the human serum or plasma sample.
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