. 2012 Nov 16;1(2):A0013. doi: 10.5702/massspectrometry.A0013

Table 1. Differences between calculated and observed m/z values for phosphatidylcholine (PC) and phosphatidylethanolamine (PE) peaks observed in the averaged mass spectra after mass-correction using confirmed PC (34 : 1) [M+K]⁺.

Compound	Ion type	Formula	Calculated m/z	Observed m/z	Error (ppm)
PC (32 : 0)	[M+Na]⁺	C₄₀H₈₀NO₈PNa⁺	756.5514	756.5493	−2.8
PC (32 : 0)	[M+K]⁺	C₄₀H₈₀NO₈PK⁺	772.5253	772.5242	−1.4
PC (34 : 1)	[M+Na]⁺	C₄₂H₈₂NO₈PNa⁺	782.5670	782.5660	−1.3
PE (38 : 4)	[M+2K−H]⁺	C₄₃H₇₇NO₈PK₂⁺	844.4656	844.4623	−3.9
PE (40 : 6)	[M+2K−H]⁺	C₄₅H₇₇NO₈PK₂⁺	868.4656	868.4612	−5.0

Table 1. Differences between calculated and observed m/z values for phosphatidylcholine (PC) and phosphatidylethanolamine (PE) peaks observed in the averaged mass spectra after mass-correction using confirmed PC (34 : 1) [M+K]+.