. 2014 Dec 8;167(1):118–136. doi: 10.1104/pp.114.252395

Table II. Conditions for the regiochemical assignment of FAs at sn-1, sn-2, and sn-3 positions in glycerolipids from P. tricornutum.

Analyzed Lipids	Polarity	Ion Analyzed	MS2 Fragment Properties	References
Phospholipids
PC	+	[M + H]⁺	[M+H-R₂CH = C = O]⁺ > [M+H-R₁CH = C = O]⁺	Hsu and Turk (2003)
PE	–	[M – H]^–	[R₂COO]^– > [R₁COO]^–	Hsu and Turk (2000a)
PG	–	[M – H]^–	[M-H-R₂COOH]^– > [M-H-R₁COOH]^–	Hsu and Turk (2001)
PI	–	[M – H]^–	M-H-R₂COOH]^– > [M-H-R₁COOH]^–	Hsu and Turk (2000b)
Nonphosphorus glycerolipids
SQDG	–	[M – H]^–	[M-H-R₁COOH]^– > [M-H-R₂COOH]^–	Zianni et al. (2013)
ASQ	–	[M – H]^–	[M-H-R₁COOH]^– > [M-H-R₂COOH]^–	Naumann et al. (2011)
MGDG	+	[M + Na]⁺	[M+Na-R₁COO^–]⁺ > [M+Na-R₂COO^–]⁺	Guella et al. (2003)
DGDG	+	[M + Na]⁺	[M+Na-R₁COO^–]⁺ > [M+Na -R₂COO^–]⁺	Guella et al. (2003))
DGTA	+	[M + H]⁺	[M+H-R₂COOH]⁺ > [M+H-R₁COOH]⁺	By analogy with phospholipid diacylglycerol moiety
Nonpolar glycerolipids
DAG	+	[M + NH₄]⁺	[M+NH₄-R₁COONH₄]⁺ > [M+NH₄-R₁COONH₄]⁺	Camera et al. (2010)
TAG	+	[M + NH₄]⁺	[M+NH₄-R_1/3COO^–]⁺ > [M+ NH₄-R₂COO^–]⁺	Hsu and Turk (2010)