Fig. 3.

Representative negative-ion 2D electrospray ionization mass spectrum of a diluted chloroform extract of mouse dorsal root ganglia after treatment in situ with Fmoc chloride. A conventional electrospray ionization mass spectrum of Fmoc-glycerophosphoethanolamine (GPEtn) was acquired in the negative-ion mode directly from a diluted mouse dorsal root ganglia lipid extract after derivatization with Fmoc chloride (Han et al. 2005a). Analyses of Fmoc–GPEtn building blocks in the second dimension including the Fmoc moiety, fatty acyl carboxylaytes, and lyso plasmenylethanolamine (pGPEtn) ions by precursor-ion (PI) scanning and neutral loss (NL) scanning were performed. ‘IS’ denotes internal standard; (m:n) indicates an acyl chain containing m carbons and n double bonds; FA stands for fatty acyl chain. Each of the broken lines indicates the crossing peaks (fragmental ions) of a molecular ion with Fmoc–GPEtn building blocks. All mass spectral traces were displayed after normalization to the base peak in each individual spectrum.