Characterization of prostaglandins by LC/APCI-MS

Prostaglandins (PGs; PGA1, PGB1, PGD2, PGE1, PGE2 and 6-keto-PGF1α) have been determined by LC/APCI-MS. The positive ion spectra obtained for PGs except for PGB1 exhibited base peaks corresponding to ions arising from the loss of H2O from the (M+H)+ and, when the solution containing AcONH4 as mobile phase was used, ions from the addition of NH4+. However, only PGB1 showed the protonated ion (M+H)+ as a base peak. The detection limits of each of the PGs were about 100 ng (on-column) by TIC (total ion current) mode and on SIM (selected ion monitoring) mode, good correlation factors were obtained for each of the PGs (γ>0.998). The detection limits and the relative standard deviations were 26 ng (on-column) and about 5% (n=5), respectively.