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Table 1 Assignment of main infrared peaks (cm−1) of standard materials and compounds

From: Erratum to: A study of the deterioration of aged parchment marked with laboratory iron gall inks using FTIR‑ATR spectroscopy and micro hot table

Absorption maximum (cm−1) Assignment
Collagenous materials
Collagen Parchment
3315 s, br 3302 Amide A: first component of vN–H in Fermi resonance with the amide II overtone (overlapping with v as O–H (3447 br) and v s O–H (3240 br) of structural H2O)
3072, m-w, br 3072 Amide B: (second component of vN–H in Fermi resonance with the amide II overtone)
2958 2926 vC–H
1640 s 1644 Amide I: vC=O with small contributions from vC–N and δN–H) [overlapping with δH–O–H (approx. 1610) of structural H2O]a
1545 s 1538 Amide II: (vC–N with contributions from δ ip N–H)b
1454 m-w 1448 δCH2 of Pro-
1405 w 1408 δ ip C–O–H (carboxylic side chains) and δNH2
1340 w 1334 wCH2/δC–H (methine)
1241 m-w 1230 Amide III: (vC–N + δN–H with contributions from vC–C and δipC=O)b
1082, 1032 1084, 1031 Breathing of proline ring [68] with carbohydrate vC–O and vC–O–C (glycosylation sites) [69]/parchment: additional esters [70]
Gallic acid [40, 73, 74]
3498 vO9H, vO11H
3366 vO10H
3284 vO14H (COOH)
3065, 2996, 2844 vC2–H, vC6–H
2673, 2632, 2575, 2512 vO14H (–COOH dimers)
1703 vC=O
1668, 1648 vC=O (–COOH dimers)
1612,1542,1484, 1468, 1427, 1387, 1321 vC=C (aromatic ring vibrations)
1268 vC–O
1221 δ(i-p) C–O–H
1184 vC1–C7+ vC–H
1099 vC1–C7+ δC–O–H
1028 Aromatic asym-, sym-breathing, vC1–C7 + vC–OH (phenol)
904 vC-O +δ(o-o-p) C-O-H (dimer band) + δ(o-o-p) of ring
867 δ(i-p) C–H
767 δ(o-o-p) C–H (out-of-phase)
735 δ(o-o-p) C–H (out-of-phase) + τC–OH (torsion)
703 Aromatic ring puckering
636 Aromatic ring puckering + δ(o-o-p) C–O–H (phenolic)
559 δ(o-o-p) C–O–H (phenolic)
492 τC—aromatic ring
Gum Arabic
3352 vOH
2932 vC–H
1604 v as COO
1418 v s COO
1146(sh), 1068, 1035(sh) vC–O
Iron (II) sulfate heptahydrate
3336 vOH
1652 δOH in water
1092 v 3 SO4 2−
977 v 1 SO4 2−
619 v 4 (asym-) SO4 2−
LIG ink formulation
3415 vOH in water
1645 δOH in water
1094 v 3 SO4 2−
977 v 1 SO4 2−
628 v 4 (asym-) SO4 2−
LIGG ink formulation
3439 vH–O in polysaccharide (gum Arabic) and water
2931 vC–H
1640 δOH in water overlapping with v asCOO in polysaccharide (gum Arabic)
1424 v s COO in gum Arabic
1083 v 3 SO4 2− overlapping with vC–O in gum Arabic
1146(sh), 1035(sh) vC–O in gum Arabic
604 v 4 (asym-) SO4 2−
  1. v stretching, δ bending, d deformation, ip in-plane, sh shoulder
  2. aAccording to Ref. [24]
  3. bAccording to Refs. [24, 46]