Scheme 1.

Fragmentation Processes Proposed for the [M − H]⁻ Ion of 4-Pregnene-11β,20,21-triol-3-one 21-Sulfate (SS427)^a

^a The m/z values of the analogous ions that give mass shifts arising from ³⁴S-, ²H₂-, and ³⁴S- and ²H₂-labeled isotopologues are shown after a slash. The slash and m/z values are not shown if MSⁿ experiments with the isotopologues were not performed.