Table 1. List of the molecules observed in the mouse footpad.

Observed m/z	Theoletical m/z	tolerance	ion	possible molecular structure
618.4	618.48	0.08	[M+H]+	Ceramide-1-phosphate (d18∶1/C16∶0)
630.5	630.62	0.12	[M−H2O+H]+	Ceramide (d18∶1/C24∶1)
646.46	646.51	0.05	[M+H]+	Ceramide-1-phosphate (d18∶1/C18∶0)
713.49	713.49	0	[M+K]+	Sphingomyelin (d18∶1/C14∶0)
730.57	730.63	0.06	[M+H]+	Ceramide-1-phosphate (d18∶1/C24∶0)
741.51	741.53	0.02	[M+K]+	Sphingomyelin (d18∶1/C16∶0)
744.68	744.72	0.04	[M−H2O+H]+	Ceramide (d18∶1/C32∶0)
758.7	758.72	0.02	[M−H2O+H]+	Ceramide (d18∶1/C32∶1h)
769.52	769.56	0.04	[M+K]+	Sphingomyelin (d18∶1/C18∶0)
796.53	796.52	−0.01	[M+K]+	Phosphatidylcholine (C16∶0/C18∶2)
798.55	798.54	−0.01	[M+K]+	Phosphatidylcholine (C16∶0/C18∶1)
844.54	844.52	−0.02	[M+K]+	Phosphatidylcholine (C16∶0/C22∶6)
866.65	866.67	0.02	[M+K]+	Glucosylceramide (d18∶1/C24∶0h)
869.67	869.69	0.02	[M+K]+	Triacylglycerol (C16∶0/C16∶0/C18∶2)
880.62	880.69	0.07	[M+K]+	Glucosylceramide (d18∶1/C26∶1)
895.64	893.71	0.07	[M+K]+	Triacylglycerol (C16∶0/C18∶2/C18∶1)
894.65	894.67	0.02	[M+K]+	Glucosylceramide (d18∶1/C26∶0h), (t18∶1/C26∶1)
897.72	897.73	0.01	[M+K]+	Triacylglycerol (C16∶0/C18∶1/C18∶1)
906.63	906.7	0.07	[M+K]+	Glucosylceramide (d18∶1/C28∶0)

Underlined molecules are only predicted molecules based on the localization and molecular mass.