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. 2017 Mar 10;18(3):605. doi: 10.3390/ijms18030605

Table 6.

Values of m/z from positive ionization that are tentatively ascribed to glycosphingolipid species according to the neutral mass value and the LipidMaps database (http://www.lipidmaps.org). The elemental composition that closely matches the experimental mass was chosen amongst those annotated in the LipidMaps database. Mexp is the exact mass calculated from the experimental m/z value, and MTh is the theoretical exact mass corresponding to the proposed elemental composition.

No. m/z Ion Exact Mass (Mexp − MTh) Elemental Composition Glycosphingolipid Class Tentative Ceramide
1 1013.75 [M + 2H]+2 2025.11 (+0.37) C94H168N4O42 Globo/Lacto/Neolacto -Cer(d18:1/22:0)
2 1187.87 [M + 2H]+2 2373.23 (+0.49) C107H188N6O51 Acidic -Cer(d18:1/22:0)
3 984.72 [M + 2H]+2 1967.07 (+0.35) C91H162N4O41 Acidic -Cer(d18:1/22:0)
4 797.92 [M + 3H]+3 2390.25 (+0.48) C108H191N5O52 Lacto/Neolacto -Cer(d18:1/22:0)
5 875.31 [M + 3H]+3 2623.30 (−0.39) C116H202N6O59 Acidic (4 isomers) -Cer(d18:1/22:0)
6 855.97 [M + 3H]+3 2565.29 (−0.43) C114H200N6O57 Lacto/Neolacto -Cer(d18:1/20:0)
2565.32 (−0.46) C116H204N4O57 Neolacto (2 isomers) -Cer(d18:1/26:1)
7 1158.83 [M + 2H]+2 2315.25 (+0.39) C107H190N4O49 Acidic (3 isomers) -Cer(d18:1/26:0)
778.58 [M + 2H + NH4]+3 2315.25 (+0.43) C107H190N4O49 Acidic (3 isomers) -Cer(d18:1/26:0)
[M + 2H + NH4]+3 2298.23 (+0.41) C106H187N5O48 Lacto/Neolacto (2 isomers) -Cer(d18:1/26:1)
8 836.62 [M + 3H]+3 2507.31 (+0.47) C114H202N4O55 Neolacto -Cer(d18:1/24:0)
9 955.72 [M + 2H]+2 1909.03 (+0.39) C88H156N4O40 Acidic (3 isomers) -Cer(d18:1/22:0)
10 926.70 [M + 2H]+2 1851.05 (+0.33) C88H158N2O38 Globo -Cer(d18:1/26:1)
1851.02 (+0.36) C86H154N4O38 Lacto/Neolacto -Cer(d18:1/20:0)
11 1129.84 [M + 2H]+2 2257.21 (+0.45) C104H184N4O48 Neolacto (2 isomers)/Acidic -Cer(d18:1/26:1)/-Cer(d18:1/26:0)
759.23 [M + 2H + NH4]+3 2257.21 (+0.45) -Cer(d18:1/26:1)/-Cer(d18:1/26:0)
12 897.66 [M + 2H]+2 1793.04 (+0.26) C86H156N2O36 Lacto/Neolacto (2 isomers) -Cer(d18:1/24:0)
13 946.722 [M + H]+ 945.7116 (+0.0025) C52H99NO13 Neutral -LacCer(d18:1/22:0)
14 1100.81 [M + 2H]+2 2199.20 (+0.40) C102H182N4O46 Neolacto -Cer(d18:1/24:0)
739.89 [M + 2H + NH4]+3 2199.20 (+0.41) -Cer(d18:1/24:0)
[M + 3H]+3 2216.16 (+0.47) C100H177N5O48 Lacto/Neolacto (2 isomers) -Cer(d18:1/20:0)
15 817.28 [M − H2O + 3H]+3 2467.25 (−0.42) C110H194N4O56 Neolacto (2 isomers) -Cer(d18:1/20:0)
[M + 2H + NH4]+3 2432.26 (−0.47) C110H193N5O53 Neolacto (3 isomers) -Cer(d18:1/24:1)
16 1071.79 [M + 2H]+2 2141.16 (+0.40) C99H176N4O45 Acidic (9 isomers) -Cer(d18:1/24:0)
720.54 [M + 2H + NH4]+3 2141.16 (+0.40) -Cer(d18:1/24:0)
[M + 3H]+3 2158.12 (+0.47) C97H171N5O47 Acidic -Cer(d18:1/20:0)
17 1042.77 [M + 2H]+2 2083.12 (+0.40) C96H170N4O44 Acidic (4 isomers) -Cer(d18:1/24:0)
701.20 [M + 2H + NH4]+3 2083.12 (+0.42)

Values of m/z provided here were detected under positive ionization. From the observed m/z value the corresponding neutral mass value (M) was calculated by taking into account the posible ions [M + nH]+n, [M + NH4 + (n − 1)H]+n, [M + (n − 1)NH4 + (n − 2)H]+n or [M + nNH4]+n where n = 2 or 3. Ganglioside species annotated in the LipidMaps database (http://www.lipidmaps.org) that mached the calculated M within an error of 0.5 Da were considered as tentative ganglioside species corresponding to the observed m/z. The exact mass corresponding to the elemental composition of the selected ganglioside species is provided along with the error (between brackets) for the calculated M from the m/z value. Mexp is the exact mass calculated from the experimental m/z value, and MTh is the theoretical exact mass corresponding to the proposed ganglioside elemental composition. The ceramide moiety is only annotated in this table because of the potential variability of the sugar moiety that was not determined.