. Author manuscript; available in PMC: 2022 Jun 22.

Published in final edited form as: Chem Res Toxicol. 2021 Jul 28;34(8):1910–1925. doi: 10.1021/acs.chemrestox.1c00181

Table 4.

Fragment Ions (Negative Ionization Mode) Detected during HRMS/MS Analysis of C-CTX-1/-2-GlcA ([M−H]⁻, m/z 1315.6)^a

m/z	ion formula	RDBE	identity	Δ_m (ppm)
1315.6482	[C₆₈H₉₉O₂₅]⁻	19.5	[M−H]⁻	0.08
1297.6366	[C₆₈H₉₇O₂₄]⁻	20.5	[M−H−H₂O]⁻	−0.71
1197.6200	[C₆₄H₉₃O₂₁]⁻	18.5	[M−C₄H₆O₄−H]⁻^b	−1.2
193.0356	[C₆H₉O₇]⁻	2.5	[GlcA−H]⁻	1.2
175.0248	[C₆H₇O₆]⁻	3.5	[GlcA−H−H₂O]⁻	−0.06
157.0141	[C₆H₅O₅]⁻	4.5	[GlcA−H−(H₂O)₂]⁻	−0.93
129.0194	[C₅H₅O₄]⁻	3.5	[GlcA−H−H₂O−CO₂]⁻	0.53
113.0244	[C₅H₅O₃]⁻	3.5	[GlcA−H−H₂O−CO₂]⁻	−0.15
99.0088	[C₄H₃O₃]⁻	3.5	[GlcA−H−H₂O−CO−CH₂O]⁻	0.33
95.0139	[C₅H₃O₂]⁻	4.5	[GlcA−H−(H₂O)₂−CO₂]⁻	0.50

Data were obtained using a collision energy of 90 eV. Table shows observed m/z, predicted ion formula, ring double bond equivalents (RDBE), suggested identities, and mass error (Δ_m in ppm) relative to the expected m/z.

Neutral loss from GlcA moiety.