Analysis of 13 kinds of steroid hormones in raw milk using modified QuEChERS method combined with UPLC-QTOF-MS

Thirteen kinds of steroid hormones in raw milk (cow, goat and buffalo milk) were analyzed with ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF-MS) after extraction and cleanup with the modified QuEChERS method. These steroid hormones included 17β-estradiol, estriol, estrone, diethylstilbestrol, progesterone, melengestrol acetate, megestrol acetate, chlormadinone acetate, 19-nortestosterone, metandienone, boldenone, epitestosterone, and testosterone. The limits of detection for the raw milk basing on 3 times the signal to noise ratios (S/N=3) was in range of 0.07-0.51 µg kg−1, and the limits of quantification (basing on S/N=10 method) covered the ranges from 0.23 to 1.7 µg kg−1. With matrix external standard method, the substances presented recoveries over the range 74.2-99.7%. Qualitative analysis was also done in the mass/mass spectrum (MS/MS) mode and each debris structure of 13 kinds of steroid hormones was achieved. The methodology was then applied in real raw milk samples which were collected in several areas of China and the progesterone was detected with high level.