Fig. 1. Electrospray ionisation mass spectra showing molecular species composition of carp liver microsome phospholipids. As phosphatidylcholine (PC) species were partially sodiated under positive ionisation conditions (spectra not shown), they were analysed from precursor scans of m/z 184 (A) that selectively detected [M+H]⁺ molecular ions. Acidic phospholipids were detected as molecular ions under negative ionisation conditions (B). As plasmenyl phosphatidylethanolamine (PE) species were not detected in this spectrum, PE species were quantified as sodium adducts from constant neutral loss scans of m/z 141 under positive ionisation conditions (C) after the addition of 5 mmol l^-1 NaI. Such neutral loss scans selectively detected diacyl but not alkenylacyl PE species. Phosphatidylinositol (PI) species were identified from precursor scans of m/z 241 (D), while phosphatidylserine (PS) and phosphatidylglycerol (PG) were identified from constant neutral loss scans of m/z 87 and precursor scans of m/z 153, respectively (data not shown).