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. 2012 Oct 10;153(1):63–71. doi: 10.1093/jb/mvs121

Fig. 3.

Fig. 3

Identification and determination of steroids by the SigmaFit algorithm and LC-TOF MS analysis. The chromatograms of the preparations from the testis by TOF MS analysis developed in this study (A) and theoretical abundances of testosterone containing an isotope (B). A δ-value was calculated by the program ‘sigmaFit algorithm’ after comparing the two chromatograms A and B. The δ-value between 0 and 1.0 shows higher identification. In this case, small δ-value was observed at 0.0118 and the mass error was only 2.0 mDa showing that TS in the sample was identified. The identification of other steroids was performed by the same procedure using sigmaFit algorithm. Identically, TS precursors were identified from testis. Product-ion spectrums were obtained for TS by MS/MS analysis (C). SRM of TS was used for quantitative analysis as described in Materials and Methods section (D).