Table 2.

Exact mass measurements for SYWKQCAFNAVSCFamide (with a disulfide bridge) from the analysis of freshly dissected tissue samples or tissue extracts using MALDI-FTMS

Tissue	Sample type*	Measured m/z†	Error (p.p.m.)‡
Supraoesophageal ganglion (brain)	DT and E	1650.7160	–1.9
Eyestalk	E	1650.7220	1.3
Sinus gland (SG)	DT and E	ND
Commisural ganglion (CoG)	DT and E	1650.7205	0.8
Stomatogastric ganglion (STG)	DT	ND
Pericardial organ (PO)	DT	ND§
Posterior midgut caecum (PMC)	DT	ND

Peptide identity, SYWKQCAFNAVSCFamide (with disulfide bridge); ion identity, [M+H]⁺; calculated m/z, m/z 1650.71918 (monoisotopic)

ND, not detected

^*DT, direct tissue; E, extract

^†Average of three or more calibrated mass measurements. Spectra were calibrated using either poly(propylene glycol) or VYRKPPFNGSIFamide (m/z 1423.7845), APSGFLGMRamide (m/z 934.4927), and pQDLDHVFLRFamide (m/z 1271.6531 and m/z 817.4832)

^‡Mass measurement error in p.p.m.

^§A peak detected at m/z 1652.7309, which may correspond to reduced SYWKQCAFNAVSCFamide (calculated m/z 1652.7348)