. 2012 Oct;78(19):6866–6874. doi: 10.1128/AEM.01681-12

Table 2.

Main IPLs identified in the three soil thaumarchaeotal (enrichment) cultures with the characteristic ions, polar head groups, and major core GDGTs

Peak^a	Characteristic ion(s) (mass in Da)		IPL head group^c	Main core GDGT(s)
Peak^a	MS¹^b	Lost in MS²	IPL head group^c	Main core GDGT(s)
1	1,471; [M+NH₄]⁺	179	MH	Crenarchaeol
2	1,639, 1,637; [M+NH₄]⁺	179, 341	DH	GDGT-2, GDGT-3
3	1,635; [M+NH₄]⁺	179, 341	DH	GDGT-4
4	1,633; [M+NH₄]⁺	179, 341	DH	Crenarchaeol
5	1,655; [M+NH₄]⁺^d	179, 197, 341, 359	DH	OH-GDGT-2
6	1,651; [M+NH₄]⁺	179, 197, 341, 359	DH	OH-GDGT-4
7	1,797; [M+NH₄]⁺	179, 341, 503	TH	GDGT-4
8	1,795; [M+NH₄]⁺	179, 341, 503	TH	Crenarchaeol
9	1,558; [M+Na]⁺	180, 242, 260	PH	GDGT-4
10	1,556; [M+Na]⁺	180, 242, 260	PH	Crenarchaeol
11	1,728; [M+Na]⁺	162, 180, 242, 260	HPH	GDGT-0
12	1,726; [M+Na]⁺	162, 180, 242, 260	HPH	GDGT-1
13	1,724; [M+Na]⁺	162, 180, 242, 260	HPH	GDGT-2
14	1,718; [M+Na]⁺	162, 180, 242, 260	HPH	Crenarchaeol

The numbers refer to peaks indicated in Fig. 3.

Typically, [M+NH₄]⁺, [M+Na]⁺, and [M+H]⁺ ions were observed; the ion reported was used for the MS² experiment.

MH, monohexose; DH, dihexose; TH, trihexose; PH, phosphohexose; HPH, hexose-phosphohexose (Fig. 1).

Ions at 1,657 and 1,653 Da are also present in smaller relative amounts (comparable to that of peak 6) and are likely derived from DH IPLs with OH-GDGT-1 and OH-GDGT-3 as the core lipids.