(A) Extracted Ion Chromatogram (obtained by extraction of the [M+Na]+ species) for 6-dEB (top) and analogs with the molecular formula C22H40O6, corresponding to products derived from incorporation of a single ethylmalonyl extender unit (bottom). (B) Full mass spectrum of 6-dEB (13.5 min; top) and Peak II (14.0 min; bottom). In each case, ions corresponding to at least three of the following species were observed: [M+H-2H2O]+, [M+H-H2O]+, [M+H]+, and [M+Na]+.