Moreover, the extensive fragmentation pattern observed upon CID of charge-switched FAs only further complicates accurate identification, particularly in the case of complex mixture analysis. While the ion/ion approach described above can confidently distinguish anteiso and iso branched lipid isomers, this approach is useful only when the straight-chain isomer is not present. As the CID spectra of charge-switched iso and straight-chain lipid isomers are nearly identical, structural assignments in the absence of an anteiso branched lipid isomer can be ambiguous. To circumvent the shortcomings of the shotgun ion/ion approach, an alternate LC-MS/MS strategy utilizing post-column wet-chemical charge switch derivatization was developed. Importantly, the presented LC-MS/MS charge switching strategy not only enhances mixture analysis performance, but also eliminates ambiguities in the assignment of isomeric saturated FA structures. Specifically, this platform includes reversed phase liquid chromatography (RPLC) interfaced with a commercially available triple quadrupole mass spectrometer. The experimental set up is depicted in Figure . As a first step, [FA -H + MgTerpy] + complex cations were first generated in solution. To do so, MgCl2, 2,2′:6′,2′′-Terpyridine, and a synthetic FA standard were combined in a methanolic solution at room temperature. Next, the methanolic solution was infused directly into the mass spectrometer. Upon ESI, abundant charge-switched FA anions were observed. Notably, the MS/MS spectra of [14:0(12Me) -H + MgTerpy] + (m/z 498) and [14:0(13Me) -H + MgTerpy] + (m/z 498) obtained on the triple quadrupole mass spectrometer following condensed-phased FA derivatization (Figure ) are identical to those obtained utilizing the gas-phase ion/ion approach described previously for non-esterified FA structures.