Positive and negative ion mode

DB = Double bond; O = ether-linkage instead of ester-linkage

Lipid classes

Type of overlap

m/z

Examples

DB containing classes

[M+DB+13C2] ≈ [M] *

0.009

[PC 32:1+H+13C2]+ ≈ [PC 32:0+H]+

Glycerolipids

[M] ≈ [M+CH2+O]

0.036

 [PC 33:1+H]+ ≈  [PC O-34:1+H]+

Sphingolipids

[M] ≈ [M+CH2-DB-OH]

0.036

[SM t42:2] ≈ [SM d43:1]

PI - PS

[PI] ≈ [PS+6CH2+5DB+13C]

0.002

[PI 34:1-H]-  ≈  [PS 40:6-H+13C]-

PC - SM

[PC+13C] ≈ [SM-OH2 +4CH2-DB]

0.065

[PC 38:3+13C] ≈ [SM d42:2]

Positive ion mode

DB = Double bond

Lipid classes

Type of overlap

m/z

Examples

DB containing classes

[M+Na]+ ≈ [M+2CH2+3DB+H]+

0.002

[PC 34:1+Na]+ ≈ [PC 36:4+H]+

PC - PS

[PC+H]+ ≈ [PS+DB+H]+

0.073

[PC 32:0+H]+ ≈ [PS 32:1+H]+

DG - CE

[CE X:Y+NH4]+ ≈ [DG X+30:Y+NH4]+

0.015

[CE 18:1+NH4]+ ≈ [DG 38:1+NH4]+

 

Negative ion mode

DB = Double bond; O = ether-linkage instead of ester-linkage

Lipid classes

Type of overlap

m/z

Examples

DB containing classes

[M+35Cl]- ≈ [M+DB+37Cl]-

0.019

[PC 34:1+35Cl]- ≈ [PC 34:2+37Cl]-

PA - CL2-

[PA X:Y-H]- ≈ [CL 2X:2Y-2H]2-

0.018

[PA 34:2-H]- ≈ [CL 64:4-2H]2-

 

Isobaric fragment ions

DB = Double bond; O = ether-linkage instead of ester-linkage

Lipid classes

Type of overlap

m/z

Examples

FA fragments

FA X:Y(+O) ≈ FA X+4:Y+6(-CO)

0.021

[FA 18:0-H]- ≈ [FA 22:6-H-CO2]-

FA fragments

FA X:Y(+O) ≈ FA X+3:Y-1(-CO)

0.073

[FA 20:4-H]- ≈ [FA 23:3-H-CO2]-