Table 1.

Identified ions of endogenous ceramides in ToF-SIMS spectra of the stratum corneum in human skin cross sections and molecular structures of the assigned ceramides (after⁶).

Nominal mass (m/z)	Chemical formula	Molecular assignment	Observed mass (m/z)	Theoretical mass (m/z)
Negative ions
664	C42H82NO4−	NH(42:0)/NP(42:1)	664.610	664.624
666	C42H84NO4−	NP(42:0)	666.618	666.640
680	C42H82NO5−	AH(42:0)/AP(42:1)	680.634	680.619
682	C42H84NO5−	AP(42:0)	682.648	682.634
692	C44H86NO4−	NH(44:0)/NP(44:1)	692.643	692.655
694	C44H88NO4−	NP(44:0)	694.638	694.671
708	C44H86NO5−	AH(44:0)/AP(44:1)	708.662	708.650
710	C44H88NO5−	AP(44:0)	710.665	710.666
720	C46H90NO4−	NH(46:0)/NP(46:1)	720.646	720.686
722	C46H92NO4−	NP(46:0)	722.677	722.702
736	C46H90NO5−	AH(46:0)/AP(46:1)	736.681	736.681
738	C46H92NO5−	AP(46:0)	738.711	738.697
Positive ions
688	C42H83NO4 Na+	NH(42:0)/NP(42:1)	688.558	688.621
690	C42H85NO4 Na+	NP(42:0)	690.605	690.637
704	C42H83NO5 Na+	AH(42:0)/AP(42:1)	704.632	704.616
706	C42H85NO5 Na+	AP(42:0)	706.672	706.632
716	C44H87NO4 Na+	NH(44:0)/NP(44:1)	716.660	716.653
718	C44H89NO4 Na+	NP(44:0)	718.660	718.668
732	C44H87NO5 Na+	AH(44:0)/AP(44:1)	732.660	732.648
734	C44H89NO5 Na+	AP(44:0)	734.625	734.663
744	\C46H91NO4 Na+	NH(46:0)/NP(46:1)	744.669	744.684
746	C46H93NO4 Na+	NP(46:0)	746.692	746.700
760	C46H91NO5 Na+	AH(46:0)/AP(46:1)	760.679	760.679
762	C46H93NO5 Na+	AP(46:0)	762.681	762.695